Question

The electric power of heater is 0.5 kW .It is used for 20 min, the generated heat will be -
a) 2.5×$10^{-2}$ J
b) 10 J
c) 4 J
d) 6.0×$10^{5}$ J
(ANSWER WITH STEPS)

Answer 1

Answer:4

Explanation:

Answer 2

The electric power of heater is 0.5 kW. It is used for 20 min, thus, the generated heat will be:

d) 6.0x 10⁵ J

• We know that,

        Heat Generated = I²RT                        eq(1)

        Power (P) = I²R                                     eq(2)

• Therefore, from eq(1) and eq(2),

        Heat Generated = PxT

• Now, As per the question, Power (P) =  0.5 kW

                                                                     = 0.5x1000 W

                                                                     = 500 W

• And, Time (T) = 20 min

                               = 20x60 sec

                               = 1200 sec

• Thus, Heat Generated = PxT

                                              = (500x1200) J

                                              = (600000) J

                                              = 6.0x10⁵ J