alleryStart learning →One commercial unit of electricity equals?
- One kilowatt hour
- One watt second
- One kilowatt second
- One watt hour
Show answer and solution
Correct answer: A. One kilowatt hour
A commercial unit of electrical energy is one kilowatt hour.
ICSE Class 8 Electricity — practice questions
Explore 23 free Electricity questions in ICSE Class 8 Physics. Open each question or exercise to read its content, reference answers and available explanation.
Practise Electricity with Quill →Electricity questions and exercises with answers
Showing questions 1–23 of 23.
One commercial unit of electricity equals?Read the answer and worked solution →A fuse is connected how relative to its protected appliance?Read the answer and worked solution →An excessive current opens a fuse mainly by?Read the answer and worked solution →Household appliances are parallel mainly to receive?Read the answer and worked solution →One lamp is switched off in a parallel home circuit. Others?Read the answer and worked solution →Which appliance part is connected to the protective earth?Read the answer and worked solution →Damaged insulation lets live touch neutral directly. This is?Read the answer and worked solution →Too many appliances on one socket mainly risk?Read the answer and worked solution →A fuse rated far above a circuit's safe current may?Read the answer and worked solution →Four cells are joined end-to-end in one chain. This is?Read the answer and worked solution →A meter rises from 1226 kWh to 1244 kWh. Energy used?Read the answer and worked solution →How much energy does a 300 W fan use in 2 hours?Read the answer and worked solution →Ten 8 W lamps run for 5 hours. Total energy used?Read the answer and worked solution →A 200 W device runs 3 hours daily for 30 days. Energy?Read the answer and worked solution →A 1.2 kW heater runs for 15 minutes. Energy used?Read the answer and worked solution →A 0.3 kW fan runs 2 h and a 0.5 kW device 4 h. Total?Read the answer and worked solution →Energy costs Rs 6 per kWh. What does 1.5 kWh cost?Read the answer and worked solution →A bill adds Rs 40 to Rs 6 per kWh. Cost for 20 kWh?Read the answer and worked solution →A 100 W lamp has a 2 kWh energy allowance. Runtime?Read the answer and worked solution →First 10 kWh cost Rs 5 each, later kWh Rs 8 each. Cost of 15 kWh?Read the answer and worked solution →A 100 W lamp becomes 20 W, used 5 h/day for 30 days. Energy saved?Read the answer and worked solution →A 1 kW heater is on for 20 min in each of 3 hours. Energy used?Read the answer and worked solution →A meter goes 620 to 638 kWh. Bill: Rs 30 plus Rs 5/kWh. Total?Read the answer and worked solution →
Worked practice questions
A fuse is connected how relative to its protected appliance?
- Across its terminals
- Along its earth path
- In series with it
- Across its switch
Show answer and solution
Correct answer: C. In series with it
A series fuse carries the appliance current and interrupts that path when it melts.
An excessive current opens a fuse mainly by?
- Melting its wire
- Expanding its wire
- Contracting its wire
- Bending its wire
Show answer and solution
Correct answer: A. Melting its wire
Excessive current heats the fuse wire until it melts and breaks the circuit.
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