MCQ
Which of the following is not a physical quantity?
- ATime.
- BImpulse.
- CMass.
- DKilogram.
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Reason $R$ : The efficiency of Carnot's engine depends not only on temperature of cold reservoir but it depends on the temperature of hot reservoir too and is given as $\eta=\left(1-\frac{ T _2}{ T _1}\right)$.
In the light of the above statements, choose the correct answer from the options given below
Where $r_{0}$ is the radius of the earth and $\sigma$ is Stefan's constant.
$(A)$ $\frac{\hat a + \hat b}{\sqrt 3}$ $(B)$ $\hat a + \widehat b$ $(C)$ $\hat a$ $(D)$ $\hat b$