Question

Rohan wants to test whether a white object or a black object would heat up faster in the Sun. The given picture shows you his experiment. These thermometers were left out in the Sun for $30$ minutes. Which of the following statements is true?

(A) Thermometer $1$ reads the same as thermometer $3$
(B) Thermometer $2$ shows a higher temperature than thermometer $3$
(C) Thermometer $3$ shows a higher temperature than thermometer $1$
(D) Thermometer $1$ reads the same as thermometer $2$

Answer 1

Hint : In order to solve this question, consider the two types of the objects that are being put in the sun and that we need to compare the temperatures for. Now, we know that out of a black and the white object, which one is more likely to heat more, thereby increasing the temperature of the thermometer.

Complete Step By Step Answer:
As we know that the black objects absorb heat much faster as compared to the bright objects and the thermometer $2$ here is showing the measurement for the black object while the thermometer $3$ is showing that for the bright object.
The object which absorbs the heat faster, will keep on becoming more and hotter with the time passing by, that will make the temperature of the thermometer $2$ more and higher with the time passing by. Thus, after $30$ minutes left in the sun, the thermometer $2$ shows a higher temperature than the thermometer $3$ .
Therefore, the option $\left( B \right)$ is the correct answer.

Note :
The heat gained by an object is directly proportional to the temperature it is going to reflect on a thermometer. In this question, it is important to know the properties of the black body radiations and the heating of the black objects which simply helps to know the answer.