Chapter 11

NCERT
Class 10
Science
Solutions
3. An electric iron of resistance 20 W takes a current of 5 A. Calculate the heat developed in 30 s.

Question:

An electric iron of resistance 20 W takes a current of 5 A. Calculate the heat developed in 30 s.

Answer:

Here,

I = 5 A, R = 20 W, t = 30s

From formula

H = I2Rt

    = 5 × 5 × 20 × 30

    = 15000 J

     = 15 KJ

Heat = 15 KJ

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