Electricity Worksheet-24

Electricity Worksheet-24

 

  1. An electric iron draws a current of 1.5 A when the voltage is 200 volts. Calculate the amount of electric charge flowing through it in one hour.

 

  1. An electric appliance draws a current of 0.4 A when the voltage is 200 volts. Calculate the amount of charge flowing through it in one hour.

 

  1. Calculate the amount of charge that would flow in 1 hour through the element of an electric bulb drawing a current of 0.2 A.

 

  1. Calculate the amount of charge that would flow in 2 hours through the element of an electric bulb drawing a current of 0.25 A.

 

  1. Calculate the amount of charge that would flow in 1 hour through the element of an electric iron drawing a current of 0.4 A.

 

  1. Draw a circuit diagram to show how two resistor are connected in series.

 

  1. A bulb is rated at 5.0 V, Calculate its (i) power and (ii) resistance.

 

  1. An electric iron has a rating of 750 W, 220 V. Calculate

(i) current passing through it, and (iii) its resistance, when in use.

 

  1. An electric lamp is marked 100 W, 220 V. It is used for 5 hours daily. Calculate (i) its resistance while glowing  (ii) energy consumed in kWh per day.

 

  1. A piece of wire of resistance 20 Ω is drawn out so that its  length is increased to twice its original length. Calculate the resistance of the wire in the new situation.

 

Answer:

  1. Q = It = 0.5 × 3600 = 1800 C.

 

  1. Q = It = 0.4 A × 1 hour = 0.4 A × 3600 s = 1440 C.

 

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

 

  1. Q = It = 0.25 A × 2 × 3600 s = 1800 C.

 

  1. Q = I t = 0.4 × 1 hour = 0.4 × 3600 s = 1440 C.

 

  1. The circuit diagram is shown in          

 

  1. V = 5.0 V, I = 100mA = 100 × 10–3 A = 10–1 A,

 

  1. Here, p = 750 W, V = 220 V

(i) AS

(ii)

 

  1. p = 100 W, V = 220 V, t = 5 h

 Energy consumed per day is given by

E = p × t = 100 W × 5 h = 500 Wh = 0.5 kWh

 

  1. if the original length and the cross – sectional area of the wire are L and A respectively,

         

When the length becomes 2L and cross – sectional area is A/2,

From (i) and (ii),