Question

Consider the following statements.
$1.$ Glaciers always melt at the bottom first.
$2.$ Calorimeters are generally made of coppers.
$3.$ The unit of latent heat is cal/g.
$4.$ If a substance contracts on heating, its co-efficient of linear expansion is negative.
Which of the statements given above are correct?

• A. $1,2$ and $3$
• B. $2,3$ and $4$
• C. $1,2$ and $4$
• D. $1,2,3$ and $4$

Answer 1

The correct option is D $1,2,3$ and $4$

1. Glaciers always melt at the bottom first, because the fluid pressure is higher at the bottom, so melting point of ice decreases.

2. Copper is a good conductor of heat and has low Specific heat capacity, so it absorbs very little heat to reach the equilibrium temperature of the system.

So the calorimeters are made of coppers.

3. Latent heat(L) equation is given as, $Q=mL$. So its unit is $cal/g$

4. Coefficient of linear expansion ($\alpha$) is given as,

$\alpha =\frac{\Delta L}{L\Delta T}$

so, if $\Delta L$ is negative, means $\alpha$ is also negative.

All statements are correct.