Define electric potential and potential difference.

What is the role of the earth wire in domestic circuits?

State Ohm’s law.

Distinguish between the resistivity and conductivity of a conductor.

What connection is used in domestic appliances and why?

An electric iron consumes energy at the rate of 420 W when heating is at the maximum rate and 180 W when heating is at the minimum rate. The applied voltage is 220 V. What is the current in each case?

A 100 watt electric bulb is used for 5 hours daily and four 60 watt bulbs are used for 5 hours daily. Calculate the energy consumed (in kWh) in the month of January.

A torch bulb is rated at 3 V and 600 mA. Calculate it’s
a) power
b) resistance
c) energy consumed if it is used for 4 hour.

A piece of wire having a resistance R is cut into five equal parts.
a) How will the resistance of each part of the wire change compared with the original resistance?
b) If the five parts of the wire are placed in parallel, how will the resistance of the combination change?
c) What will be ratio of the effective resistance in series connection to that of the parallel connection?

Water boils in an electric kettle in 15 mins after switching on. If the length of the heating wire is decreased to \(\frac{1}{3}\) of its initial value, then in how much time will the same amount of water boil with the same supply voltage?

Write any five electrical components used in electrical circuit and draw its symbol.

Kalaivani was watching at a metal pipe, one end of which is connected to a tank at the top of her building and the other end to the tap, which is near the ground level. She was admiring how the water flows from top to the bottom through the pipe. She went and asked her mother, who was an engineer.
(i) Also Kalaivani asked her mother that can she able to compare this with any other scientific concepts?
(ii) How would her mother have compared the resistance in a water pipe as well as in a conductor.
(iii) Give the expression for resistors connected in series and parallel.

Name any 5 components of a circuit. Write the uses and draw the symbols used.

Define the unit of resistance.

Differentiate series and parallel circuits.

a) What is Nichrome? 
b) what are the characteristics of a good heating element?.

How does the earth wire serve as a protective conductor which saves us from electric shocks?

Write a note on LED Bulbs.

Write a note on seven segment display.