FISIKA Kelas 12 - Energi dan Daya Listrik | GIA Academy

Summary

This educational video from DJ Academy YouTube channel explores the origins of electrical energy, its conversion into various forms like motion, sound, and light, and the factors influencing its magnitude. It explains the mathematical formulas for calculating electrical energy and power, including Ohm's Law. Practical examples, such as the brightness of a light bulb and the energy conversion in electric appliances, are discussed. The video also covers the calculation of energy consumption in households using a KWH meter and the cost of electricity. It concludes with problem-solving examples to reinforce the concepts taught.

Takeaways

• 🔌 Electricity is generated from various sources like the sun, wind, and water.
• ⚡ The devices we use daily convert electrical energy into different forms, such as motion, sound, and light.
• 💡 The amount of electrical energy an appliance uses is influenced by voltage, current, resistance, and the time it's used.
• 📐 The formula to calculate electrical energy is W = V * I * t, where W is energy in joules, V is voltage in volts, I is current in amperes, and t is time in seconds.
• 🔗 Ohm's Law states that V = I * R, which can be used to find the resistance (R) if voltage (V) and current (I) are known.
• 💡 The brightness of a light bulb is affected by its electrical power, with higher power resulting in a brighter light.
• ⏱ The power used by an electrical device can be calculated if you know its rated power and the voltage of the power source it's connected to.
• 🔥 Energy conversion to heat in electrical appliances follows the formula P = I^2 * R, where P is power in watts, I is current in amperes, and R is resistance in ohms.
• 🏡 Household electricity usage is measured in kilowatt-hours (kWh), with 1 kWh equaling 1 kilowatt used for one hour.
• 💼 The cost of electricity is calculated by multiplying the total energy used (in kWh) by the electricity rate per kWh.

Q & A

What are the various sources from which electrical energy is generated?

Electrical energy is generated from various sources such as the sun, wind, water, and more.

How is electrical energy transformed into other forms of energy?

Electrical energy can be transformed into other forms such as motion in a fan, sound and light in a television, and heat when using an iron.

What factors influence the amount of electrical energy used by an electrical device?

The amount of electrical energy used by a device is influenced by the electric current, voltage, resistance, and the duration of use.

What is the mathematical formula used to calculate electrical energy?

The electrical energy is calculated using the formula W = V * I * t, where W is energy in joules, V is voltage in volts, I is current in amperes, and t is time in seconds.

How is electrical power defined and what is its unit?

Electrical power is defined as the electrical energy transferred per unit time. Its unit is the watt (W).

What is the relationship between the power of a light bulb and its brightness?

The brightness of a light bulb is directly related to its electrical power; the higher the power, the brighter the bulb.

How can you calculate the resistance of an electrical device if you know the energy produced and the voltage?

You can calculate the resistance using the formula R = V^2 / (W / t), where R is resistance in ohms, V is voltage in volts, W is energy in joules, and t is time in seconds.

What is the formula to determine the electrical energy used by an appliance given its power and usage time?

The electrical energy used is calculated with the formula W = P * t, where W is energy in joules, P is power in watts, and t is time in seconds.

How can you find the power used by a light bulb when connected to a different voltage than its rated voltage?

The power used by the light bulb can be calculated using the formula P2 = (V2 / V1)^2 * P1, where P2 is the power used at the new voltage, V2 is the new voltage, V1 is the rated voltage, and P1 is the rated power.

What is the formula to convert electrical energy into heat, and how is it applied?

The formula to convert electrical energy into heat is V^2 / R * t = m * c * Δt, where V is voltage, R is resistance, t is time, m is mass, c is the specific heat capacity, and Δt is the change in temperature.

How is the cost of electricity calculated for household use?

The cost of electricity is calculated using the formula Cost = Energy (in KWH) * Tariff per KWH, where the energy used is converted from watt-hours to kilowatt-hours.

Outlines

00:00

🔌 Understanding Electrical Energy and Power

The first paragraph introduces the topic of electrical energy and power, emphasizing the common use of electrical appliances in daily life such as AC units, televisions, and fans. It poses questions about the origin of electrical energy and what factors affect its magnitude. The script then explains that electrical energy is generated from various sources like the sun, wind, and water, and is used to power electrical devices. It also discusses the concept of energy transformation, where electrical energy is converted into motion, sound, light, and heat. The mathematical formula for calculating electrical energy (W = V*I*t) is introduced, along with the Ohm's law (V = I*R), leading to the alternative formula for energy (W = V^2/R * t). The paragraph concludes with an invitation to watch the video to the end for a comprehensive understanding of the topic.

05:03

💡 Exploring Electrical Power and Energy Consumption

The second paragraph delves into the concept of electrical power, defined as the rate at which electrical energy is used over time. It explains that the brightness of a light bulb is an example of how power affects the performance of an electrical device. The mathematical formula for power (P = W/t) is introduced, along with its alternative forms (P = V*I and P = V^2/R). The paragraph also discusses how the specifications of an electrical device, such as power and voltage, can be used to calculate the power consumption when connected to a different voltage source. It touches on the conversion of electrical energy into heat and the formula used to measure this conversion (Q = m*c*ΔT). The script mentions the use of a kWh meter to measure household energy consumption and how electricity bills are calculated based on energy usage and the cost per kWh.

10:07

📐 Practical Calculations of Electrical Energy and Power

The third paragraph presents a series of practical problems to solve, applying the concepts and formulas introduced in the previous paragraphs. It includes calculations for determining resistance based on known energy and voltage, calculating the energy consumed by an appliance over a period of time, and determining the power used by a light bulb at a different voltage. The paragraph also covers the calculation of power across a specific resistance in a given electrical circuit and the conversion of electrical energy into heat with a focus on the time required to heat water. Each problem is solved step by step, demonstrating the application of the formulas for electrical energy and power. The paragraph concludes with a summary of the learnings from the video, encouraging viewers to continue watching for more insights.

Keywords

💡Electric Energy

Electric energy refers to the energy derived from the flow of electric charge. In the video, it is mentioned as being generated from various sources like the sun, wind, and water. It is the fundamental resource that powers electrical appliances and devices. The script discusses how electric energy is used in everyday activities, such as operating fans, televisions, and smartphones, and it is also the subject of calculations and examples throughout the video.

💡Electric Power

Electric power is the rate at which electric energy is transferred by an electric circuit. The video defines it as the 'electric energy that flows per unit of time.' It is calculated using the formula P = W/t, where P is power, W is energy, and t is time. The script uses this concept to explain the brightness of light bulbs, where a higher power results in a brighter light, illustrating the practical application of power in household electrical systems.

💡Voltage

Voltage, measured in volts, is the electric potential difference between two points. It is a key factor in determining the energy and power of an electrical device. The video script includes examples where voltage is used to calculate the resistance of an appliance and to determine the power used by a light bulb when connected to a different voltage source.

💡Resistance

Resistance is a property of materials that opposes the flow of electric current. It is measured in ohms and is used in the video to calculate the power used by an electrical device and the energy consumed. The script provides a formula W = V^2/R to demonstrate how resistance affects the energy used by an appliance, showcasing its importance in electrical calculations.

💡Current

Electric current is the flow of electric charge in a circuit, measured in amperes. The video explains how current is related to voltage and resistance through Ohm's law, V = IR, and how it is used to calculate the power and energy consumption of electrical devices. Current is a fundamental concept in the video's exploration of electrical energy and its applications.

💡Ohm's Law

Ohm's Law is a fundamental principle in electrical engineering that states the relationship between voltage (V), current (I), and resistance (R) in a circuit: V = IR. The video uses Ohm's Law to explain how to calculate the current in a circuit and subsequently the energy and power of electrical devices, emphasizing its utility in understanding and calculating electrical phenomena.

💡Energy Conversion

Energy conversion in the video refers to the process of changing one form of energy into another, such as electric energy being converted into motion, light, or heat. The script provides examples like fans converting electric energy into motion and televisions converting it into light and sound, highlighting the versatility of electric energy in powering various types of devices.

💡Electrical Appliance

An electrical appliance is a device that uses electricity to perform a function. The video discusses various appliances such as water heaters, televisions, and irons, emphasizing how they utilize electric energy for their operation. The script uses these appliances as examples to explain concepts like power, energy consumption, and efficiency.

💡Joule

The joule is the unit of energy in the International System of Units (SI). The video mentions joules when discussing the energy produced by an electric heater and the energy consumed by a light bulb. It is used to quantify the amount of work done by an electric current or the amount of energy converted or transferred.

💡Watt

A watt is the unit of power in the International System of Units (SI). The video defines it as the amount of energy used per second and uses it to calculate the power of electrical devices. The script provides formulas and examples to show how wattage relates to the energy consumption and efficiency of appliances like light bulbs and heaters.

💡Electrical Circuit

An electrical circuit is a path through which electric current flows. The video discusses series circuits and the total resistance in a circuit, which is crucial for calculating the current and power. The script uses the concept of circuits to explain how electrical devices are connected and function within a system, providing a practical context for understanding electrical principles.

Highlights

Introduction to the concept of electrical energy and its various sources like the sun, wind, and water.

Explanation of how electrical energy powers everyday devices and how it can be transformed into different forms of energy.

Discussion on the mathematical relationship between electrical energy, current, voltage, resistance, and time of use.

Introduction to Ohm's Law and its application in calculating electrical energy.

Definition and calculation of electric power, including its unit of measurement and formula.

Practical examples of how the brightness of a light bulb is influenced by its electrical power.

Explanation of how the power consumption of an electrical device changes when connected to a different voltage source.

Introduction to the concept of energy conversion into heat and the formula used to calculate it.

Explanation of how electricity meters measure household energy consumption and the calculation of electricity costs.

Tutorial on calculating the resistance of an electrical device given its energy output, voltage, and time of use.

Solution to a problem involving the calculation of energy consumption for a device with given power and usage time.

Calculation of the power used by a light bulb when connected to a different voltage source using the power formula.

Tutorial on calculating the power dissipated across a resistor in an electrical circuit given its resistance and total resistance in the circuit.

Explanation of the conversion of electrical energy into heat and the formula used to calculate the time required to heat water.

Calculation of the monthly electricity cost for household lighting based on total power consumption and the electricity tariff.

Summary of the key formulas and concepts learned in the video for calculating electrical energy and power.

Transcripts

Hai Cinta

[Musik]

halo halo teman teman selamat datang

kembali DJ Academy youtube channel

Semoga teman-teman tetap sehat dan terus

semangat ya saat belajar daring seperti

sekarang ini kita lebih banyak berada di

ruangan tertutup dan menggunakan AC kita

juga sering berkumpul di ruangan

keluarga menonton televisi dan

menggunakan kipas angin di malam hari

kita menyalakan lampu kamar sambil

santai memainkan handphone nah semua

kegiatan sehari-hari kita tadi banyak

memanfaatkan energi listrik tahukah

teman-teman Apa itu energi listrik dari

mana energi listrik tersebut berasal

serta apa saja yang mempengaruhi

besarnya energi listrik biar nggak

bingung lagi tonton videonya sampai

selesai

Hai jadi di video kali ini kita akan

belajar energi dan daya listrik Nah

teman-teman energi listrik dihasilkan

dari beragam sumber seperti matahari

angin air dan masih banyak lagi sumber

energi listrik lainnya energi listrik

tersebut dibutuhkan untuk memfungsikan

peralatan-peralatan listrik beberapa

peralatan yang kita manfaatkan tadi

merupakan hasil dari perubahan energi

listrik Yap energi listrik dapat diubah

menjadi energi lain contohnya perubahan

energi listrik menjadi gerak pada kipas

angin listrik menjadi bunyi dan cahaya

pada televisi listrik menjadi panas saat

kita menggunakan setrika dan masih

banyak contoh perubahan energi listrik

yang lain teman-teman pasti bisa

Sebutkan contoh lainnya ya Nah besarnya

energi listrik pada sebuah alat listrik

dipengaruhi oleh arus listrik beda

potensial hambatan dan waktu penggunaan

alat tersebut secara matematis energi

listrik dihitung dengan rumus w = v * *

t di video sebelumnya tentang rangkaian

arus searah kita udah bahas hukum Om

bagi yang belum nonton jangan lupa cek

video sebelumnya ya biar lebih paham

berdasarkan hukum Om v = i * r sehingga

Jika nilai V Kita substitusikan ke

persamaan w = v kali Ika Lite maka kita

peroleh persamaan energi listrik yang

lain yaitu w = x kuadrat kali er k-lite

hukum Om untuk menghitung kuat arus

sama dengan vpr sehingga W juga = v

kuadrat per er k-lite dengan W adalah

besarnya energi listrik dalam Joule V

tegangan listrik satuannya volt yg kuat

arus listrik dalam ampere er hambatan

dalam satuan Om Dante waktu satuannya

sekon Oke teman-teman bisa dimengerti ya

Pernahkah teman-teman memperhatikan dua

bola lampu yang sedang menyala mungkin

kita akan melihat intensitas terang yang

berbeda dari setiap lampu yang kita

amati tahukah teman-teman terang atau

redupnya bola lampu tersebut dipengaruhi

oleh daya listrik dimana semakin besar

daya listrik sebuah lampu maka nyala

lampu tersebut semakin terang dan

sebaliknya Jadi daya listrik

didefinisikan sebagai

energi listrik yang mengalir tiap satuan

waktu secara matematis daya listrik

dirumuskan dengan P = wpt bersamaan ini

juga bisa kita ganti dengan

mensubstitusikan persamaan energi

sehingga P juga = V kali atau p = x

kuadrat kali r&p sama juga dengan v

kuadrat per R dengan P merupakan daya

listrik satuannya watt W adalah besarnya

energi listrik dalam Joule V tegangan

listrik dalam satuan volt yg kuat arus

listrik dalam ampere er hambatan dalam

satuan Om Dante waktu satuannya sekon

jika sebuah alat listrik yang memiliki

spesifikasi tertentu dimana daya dan

tegangan tertulis pada alat P1 V1

Hai dihubungkan dengan sumber tegangan

tertentu atau V2 maka daya yang

digunakan alat tersebut adalah V2 nilai

kedua daya alat ini bisa kita bandingkan

sehingga V2 bisa kita hitung dengan

rumus V2 = V2 Pro V1 dikuadratkan kali

P1 dengan V1 tegangan yang tertulis pada

alat V2 tegangan sumber keduanya dalam

satuan volt B1 daya yang tertulis pada

alat dan V2 daya yang digunakan

satuannya what saat menggunakan beberapa

peralatan listrik seperti teko listrik

setrika atau kompor listrik terjadi

perubahan energi listrik menjadi panas

atau kalor pada peralatan-peralatan

listrik yang mengubah energi listrik

menjadi kalor berlaku persamaan

persamaan berikut dengan m massa

kg c adalah kalor jenis zat satuannya

joule per kilogram derajat Celcius dan

Delta t yang besarnya T2 kurang T1

merupakan perubahan suhu dalam satuan

derajat Celcius nah kegiatan sehari-hari

kita banyak mengatkan energi listrik

sehingga untuk mengukur penggunaan

energi listrik rumah tangga pada setiap

rumah dipasang alat ukur yang disebut

KWH meter 1 KWH = 1kw dikali satu jam =

3,6 juta Jul lalu besarnya biaya listrik

rumah tangga dihitung dengan menggunakan

rumus biaya = W * tarif per KWH dengan W

adalah energi listrik Oke teman-teman

sampai di sini bisa dipahami ya agar

teman-teman semakin paham

ayo kita selesaikan contoh soal berikut

soal pertama Diketahui sebuah alat

pemanas air digunakan selama satu sekon

energi yang dihasilkan alat 500 Joule

dan tegangannya 50volt yang ditanya

hambatan listrik pada alat berdasarkan

besaran yang diketahui hambatan pada

alat dapat kita hitung dengan rumus w =

p kuadrat per er k-lite masukkan

angkanya 500 sama dengan 50 kuadrat per

er kali satu selesaikan perhitungannya

hingga diperoleh R = 5 Om jadi jawaban

yang benar di soal kedua diketahui daya

listrik 350watt waktu penggunaan status

jam = 3600 sekon kita diminta menentukan

besarnya energi listrik yang terpakai

energi dihitung

dengan rumus w = p * t = 350 kali 3600 =

[Musik]

1260636 hui sebuah lampu dengan

spesifikasi V1 220volt dan P1 100 watt

dipasang pada tegangan V2 110volt yang

ditanya daya yang digunakan lampu atau

V2 besarnya P2 dapat ditentukan dengan

rumus V2 Pro V1 dikuadratkan kali P1 =

110° us 20 dikuadratkan kali 100

Sederhanakan angkanya V2 = 1/2

dikuadratkan kali 100 = 1/4 kali 100 V2

= 20

kuat Jawabannya d soal selanjutnya

diberikan gambar sebuah rangkaian

listrik dan diketahui r18 oem er 2 24

mr362 m&v 12 volt kita diminta

menentukan daya pada hambatan 6 Ohm atau

P3 untuk menghitung P3 kita gunakan

rumus P3 = x kuadrat kali er Nah untuk

menentukan P3 kita harus menentukan kuat

arus listrik dan hambatan total terlebih

dahulu setelah diperoleh er total 12ohm

hitung kuat arus listrik dengan rumus ih

= V PR = 12 volt per-12 Ohm = 1 ampere

P3 = x kuadrat kali r = 1 kuadrat kali

12 = 12 What jawaban yang benar

ke soal berikutnya tentang konversi

energi listrik menjadi kalor diketahui

hambatan pada alat 12 Ohm beda potensial

120 volt masa air 40 Kg kalor jenis air

4200 joule per kilogram derajat Celcius

Suhu awal 15° Celcius dan suhu akhir 80°

Celcius yang ditanya lama penggunaan

alat untuk memanaskan air tersebut atau

t kita gunakan rumus v kuadrat per er

kali t = m * deltate kemudian masukkan

angka yang diketahui lalu selesaikan

perhitungannya hingga diperoleh t = 9100

sekon = 2,5 jam Jawabannya d soal

terakhir diketahui penggunaan lampu

rumah tangga 4 lampu

10 watt 2 lampu 10 watt dan 3 lampu

40watt daya total penggunaan lampu pada

rumah tersebut sebesar 220wat digunakan

lima jam setiap hari atau 150 jam selama

satu bulan atau 30 hari tarif listrik

per KWH Rp500 kita diminta menentukan

biaya penggunaan lampu tersebut selama

satu bulan untuk menghitung biaya

penggunaan kita gunakan persamaan biaya

sama dengan energi total dikali tarif

per KWH dan energi total yang digunakan

selama satu bulan adalah w = p * t =

220wat kali 150 jam = Rp33.000 jam

jadikan ke KWH = 33 KWH lalu kita

masukkan angkanya 33 KWH chalil

Rp200 per KWH = 16500 rupiah Jawabannya

d Oke teman-teman di video kali ini kita

udah belajar persamaan-persamaan yang

digunakan untuk menghitung energi

listrik dan daya listrik bisa dimengerti

ya Nah sampai di sini pembahasan kita

tentang energi dan daya listrik Jangan

lupa tonton terus video-video terbaru di

channel kita ya sampai jumpa di video

berikutnya

[Musik]

Hi Ho