When a block of iron floats in Hg at , a fraction of its volumen= is submerged, while at temperature of a fraction is seen to be submersed. If the coefficient of volume expansion of iron is and that of mercury is , then the ratio can be expressed as:
1.
2.
3.
4.
A pendulum clock runs faster by \(5\) s per day at \(20^{\circ}\mathrm {C}\) and goes slow by \(10\) s per day at \(35^{\circ}\mathrm {C}\). It shows the correct time at a temperature of:
1. \(27.5^{\circ}\mathrm {C}\)
2. \(25^{\circ}\mathrm {C}\)
3. \(30^{\circ}\mathrm {C}\)
4. \(33^{\circ}\mathrm {C}\)
The coefficients of linear expansion of brass and steel rods are \(\alpha_1\) and \(\alpha_2\), lengths of brass and steel rods are \(l_1\) and \(l_2\) respectively. If (\(l_2-l_1\)) is maintained the same at all temperatures, Which one of the following relations holds good?
1. \(\alpha_1 l_2^2=\alpha_2l_1^2\)
2. \(\alpha_1^2 l_2=\alpha_2^2l_1\)
3. \(\alpha_1 l_1=\alpha_2l_2\)
4. \(\alpha_1 l_2=\alpha_2l_1\)
The value of coefficient of volume expansion of glycerin is 5x10-4 K-1. The fractional change in the density of glycerin for a rise of 40°C in its temperature is -
(1) 0.015
(2) 0.020
(3) 0.025
(4) 0.010
To keep constant time, watches are fitted with balance wheel made of -
(1) Invar
(2) Stainless steel
(3) Tungsten
(4) Platinum