Electricity Worksheet-23

Electricity Worksheet-23

 

  1. State which has a higher resistance : a 50 W or a 25 W lamp bulb and how many times ?

 

  1. What is the power of torch bulb rated at 2.5 V and 500 mA ?

 

  1. There are two electric bulbs, (i) marked 60 W, 220 V and (ii) marked 100 W ; 220 V. Which one of them has higher resistance ?

 

  1. Out of the two, a toaster of 1 kW and an electric heater of 2 kW, which has a greater resistance?

 

  1. What is the SI unit of electrical potential ?

 

  1. What Is meant by the statement "Potential difference between two points A and B in an electric circuit is 1 volt" ?

 

  1. Why is series arrangement not used for connecting domestic electrical appliances in a circuit ?

 

  1. Out of 60 W and 40 W lamps, which one has a higher resistance when in use ?

 

  1. Draw a schematic diagram of an electric circuit consisting of a battery of two cells, each of 1.5 V; 5 Ω, 10 Ω, 15 Ω resistors and a plug key, all connected in series.

 

  1. An electric bulb draws a current of 0.2 A when the voltage is 220 volts. Calculate the amount of charge flowing through it in one hour.

 

Answer:

A 25 W lamp has double the resistance of a 50 W lamp.

 

  1. V = 2.5 V,

I = 500 mA = 500 × 10–3 A = 5 × 10–1 A,

P = VI = (2.5 V) (5 × 10–1 A) = 1.25 W

 

  1. (i)

(ii) 

R2 is higher.

 

  1. Here; P1 = 1kW, P2 = 2kW

Resistance of the toaster, 

Resistance of the electric heater,  

     or      R1 = 2R2, i.e., R1 > 2R2.

 

  1. volt (V).

 

  1. One joule of work is done to bring one coulomb of charge from point A to point B in an electric field.

 

  1. In a series circuit, same current flows through all the electrical appliances. Since different appliances need currents of different values, so it is not advisable to connect these in series.

 

  1. We know that resistance of the lamp, or Thus, a 40 W lamp has a higher resistance than a 60 W lamp.

 

  1. The schematic diagram of the required circuit is shown in

 

  1. Q = It = 0.2 A × 1 hour = 0.2 A × 3600 s = 720 C.