NCERT Solution for Class 10 Science Chapter 12

Electricity

NCERT Books for Session 2020-2021

CBSE Board and UP Board

Exercises Questions

Page No-222

Questions No-17

# An electric heater of resistance 8 W draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.

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Heat developed in the heater is given by H = I2Rt

Where, I = 15 A, R = 8 Ω and time t = 2 hours

The rate at which heat is developed is given by

𝐻=𝐼²𝑅𝑡/𝑡=𝐼²𝑅=(15)²×8=1800 𝐽/𝑠

For more answers visit to website:

https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-12/

Rate of heat produced by a device is given by the expression for power as

P = I

^{2}RWhere,

Resistance of the electric heater,

R= 8 ΩCurrent drawn,

I= 15 AP = (15)

^{2}x 8 = 1800 J/sTherefore, heat is produced by the heater at the rate of 1800 J/s.