Question

The diagram shows a thin copper rod being heated evenly along its

length. Which of the statements is true about the rod?

(i) The bar expands and becomes lighter. (ii) The bar will become shorter in length.

(iii) The bar expands and becomes heavier.

(iv) The bar expands and its length increases.​

Answer 1

The bar expands and its length increases.

Detailed Discussion:

• First of all, let's learn about how solids expand !

• Whenever solids are uniformly heated and there is a temperature difference of $\Delta\theta$, the increase in length of solids can be expressed as :

$\boxed{ \bf\Delta L = L \times \alpha \times \Delta \theta}$

• L is initial length and $\alpha$ is the linear expansion coefficient.

_________________________

• Now, when the thin copper rod is being heated evenly along its length it will expand linearly and increase its length.

• However, since mass is same, it's weight will still remain same (neither heavy nor light).

Hope It Helps.

Answer 2

Explanation:

The bar expands and its length increases.

Detailed Discussion:

First of all, let's learn about how solids expand !

Whenever solids are uniformly heated and there is a temperature difference of \Delta\thetaΔθ , the increase in length of solids can be expressed as :

\boxed{ \bf\Delta L = L \times \alpha \times \Delta \theta}

ΔL=L×α×Δθ

L is initial length and \alphaα is the linear expansion coefficient.

_________________________

Now, when the thin copper rod is being heated evenly along its length it will expand linearly and increase its length.

However, since mass is same, it's weight will still remain same (neither heavy nor light).

Hope It Helps.