Question

The heat produced by 100W heater in 2 minutes is equal to:

Answer 1

Hint: Power is the ratio of work done to the time taken. So, substitute the values of power and time and calculate the work done which is in terms of heat produced.

Complete step-by-step solution

The heat produced is in the form of work done. Work done can be defined as the product of power and time taken. Its S.I unit is joules; it is given by

$W = P \times t$

Here, P is the power in watts and t is the time in seconds.

It is given that, \[P{\text{ }} = {\text{ }}100W\] ;\[t{\text{ }} = {\text{ }}2{\text{ }}min{\text{ }} = {\text{ }}120{\text{ }}s\] .

Substitute in the work done formula.

$
  W = 100 \times 120 \\

  W = 12000J \\

  W = 12kJ \\

 $

Note: Power is a scalar quantity. Horse power is also another unit of power \[1hp{\text{ }} = {\text{ }}764W\]. The instantaneous power can be defined as the limiting value of the power average when time approaches zero.

$P = \dfrac{{dW}}{{dt}}$

The instantaneous power can also be expressed as

$P = F.v$

Where, $v$ is the instantaneous velocity when the force is $F$ and $P$ is the instantaneous power.