Question

The radius of a ring is R and its coefficient of liner expansion is $\alpha$. If the temperature of ring increases by $\theta$, then its circumference will increases by

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

If new radius is $R^{{}^{\prime }}$
then $R^{{}^{\prime }}=R(1+\alpha \theta )2\pi R^{{}^{\prime }}=2\pi R+2\pi R\alpha \theta \therefore changeincircumference=2\pi R^{{}^{\prime }}-2\pi R=2\pi R\alpha \theta$