HARD
Earn 100

An electric refrigerator rated 400 W is used for 8 hours a day. An electric iron box rated 750 W is used for 2 hours a day. Calculate the cost (in rupees) of using these appliances for 30 days, if the cost of 1 kWh is 3.

50% studentsanswered this correctly

Important Questions on Electricity and Circuits

EASY
Which of the following terms does not represent electrical power in a circuit?
HARD
A Refrigerator of 400 W power is run for 8 hours/day. What will be the cost of the energy to operate it for 30 days? (Rate Rs. 3.00 per kwh)
EASY
How much time will be taken by a 100 W bulb to consume one unit of energy?
MEDIUM
An electric refrigerator rated 400 W is used for 8 hours a day. An electric iron box rated 750 W is used for 2 hours a day. Calculate the cost of using these appliances for 30 days, if the cost of 1 kWh is Rs.3/-.
EASY
Commercial unit of electrical energy one kilowatt hr. (1 kWh) is equivalent to:
EASY
The cost of coal is Rs 5 per kg and can produce energy of 20 MJkg-1. If a power station uses coal to produce electricity with 25 % efficiency, then the cost of coal for producing 1 unit (1 kWh-1) of electricity in Rs.
EASY
What determines the rate at which energy is delivered by a current? An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
MEDIUM
An 100 watt electric bulb is lighted for two hours daily and four 40 watt bulbs are lighted for 4 hours daily. Calculate the energy consumed in (kWh) in 30 days. 
MEDIUM

There are 60 watt lamp and 80 watt fans in a house. The lamp and the fan run for 5 hours daily. Find out the expense in a month if a unit of electricity cost Rs.4/-(Assume that one month=30 days)

EASY
An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be
EASY
In a household, five-tube lights of 40 W each are used for 5 hours and an electric press of 500 W for 4 hours every day. Calculate the total electrical energy consumed by the tube lights and press in a month of 30 days.
HARD
What is the commercial unit of electrical energy? Which uses more 250 W TV set in one hour or a 1200 W electric iron in ten minutes and how? 
MEDIUM

Soham uses a 600 W Music System for 5 hours daily. Calculate the electrical energy consumed in kWH for 30 days.

EASY
The practical unit of electrical energy 1 kWh means
EASY
What characteristics should a fuse wire have?
EASY

The diagram below shows a dual control switch circuit connected to a bulb. Out of A & B which one is the live wire and which one is the neutral wire? 

Question Image

HARD
There are 10 LED bulbs of 12 W each and 5 fans of 75 W each in a house. They are used for 10 hours per day. Prepare the bill for the month of February 2020 if the rate is Rs. 6 per unit. 
MEDIUM
An electric refrigerator rated 400 W and an electric bulb rated 100 W operates10  hours/day. What is the cost of the energy to operate it for 10 days at Rs 8.00 per kWh
EASY

200 W bulb is lighted for 2 hours. How much energy is consumed?