ICSE Class 10 Physics Question 30 of 31

Current Electricity — Question 21

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Question

Question 21

A geyser is rated '1500 W, 250 V'. This geyser is connected to 250 V mains. Calculate —

(i) the current drawn,

(ii) the energy consumed in 50 hours, and

(iii) the cost of energy consumed at ₹ 4.20 per kWh.

Answer

(i) Given,

P = 1500 W

V = 250 volt

Current drawn (I) = PV\dfrac{P}{V}

Substituting the values in the formula, we get,

I = 1500250\dfrac{1500}{250}

⇒ I = 6 A

Hence, current drawn = 6 A

(ii) energy consumed in 50 hours = ?

t = 50 h

From relation,

E = P × t

Substituting the values in the formula above, we get,

E = 1500 x 50 = 75000 Wh = 75 kWh

Hence, energy consumed in 50 hours = 75 kWh

(iii) cost of energy consumed at ₹ 4.20 per kWh = ?

Cost per unit of energy = ₹ 4.20

Cost for 75 kWh of energy = 4.2 x 7.5
= ₹ 315

Hence, cost of energy consumed = ₹ 315