Young's modulus for a steel wire is 2 x 10¹¹ Pa and its elastic limit is 2.5 x 10⁸ Pa. By how much can a steel wire 3 m long and 2 mm in diameter be stretched before the elastic limit is exceeded?

• 3.75  mm

• 7.50 mm

• 4.75 mm

• 4.00 mm

Assertion:  Transverse sound wave does not occurs in gases. 

Reason: Gases cannot sustain shearing strain.

• If both assertion and reason are true and the reason is correct explanation of assertion.

• If both assertion and reason are true but reason is not correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Which of the following graph depicts spring constant k versus length l of the spring correctly?

A body of mass 5 kg moving with a speed of 1.5 m/s on a horizontal smooth surface collides with a nearly weightless spring of force constant k = 5 N/m. The maximum compression of the spring would be

• 0.5 m

• 0.15 m

• 1.5 m

• 0.12 m

Assertion:  The size and shape of the rigid body remains unaffected under the effect of external forces. 

Reason:  The distance between two particles remains constant in a rigid body.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

If a wire is extended to a new length l, the work done is

• $\frac{\mathrm{Y} \mathrm{A}}{\mathrm{l}} \left(\mathrm{l} - \mathrm{l}\text{'}\right)$

• $\frac{\mathrm{YA}}{\mathrm{l}} {\left( \mathrm{l} - \mathrm{l}\text{'} \right)}^2$

• $\frac{1}{2} \frac{\mathrm{YA}}{\mathrm{l}} {\left( \mathrm{l} - \mathrm{l}\text{'} \right)}^2$

• $2. \frac{\mathrm{YA}}{\mathrm{l}} {\left( \mathrm{l} - \mathrm{l}\text{'} \right)}^2$

The equivalent resistance between the points X  and  Y in the following circuit diagram will be

• 10 Ω

• 5 Ω

• 7 Ω

• 3 Ω

Shear modulus is zero for

• solids

• liquids

• gases

• liquids and gases

39.

For a constant hydraulic stress on an object, the fractional change in the object's volume ( ΔV/V ) and its bulk modulus (B) are related as

• $\frac{∆\mathrm{V}}{\mathrm{V}} \propto \mathrm{B}$

• $\frac{∆\mathrm{V}}{\mathrm{V}} \propto \frac{1}{\mathrm{B}}$

• $\frac{∆\mathrm{V}}{\mathrm{V}} \propto {\mathrm{B}}^2$

• $\frac{∆\mathrm{V}}{\mathrm{V}}\propto {\mathrm{B}}^{-2}$

Assertion: The size of a hydrogen balloon increases as it rises in air. 

Reason:  The material of the balloon can be easily stretched.

• if both assertion and reason are true and the reason is the correct explanation of the assertion

• if both assertion and reason are true and the reason is not the correct explanation of the assertion

• if assertion is true but reason is false

• if both assertion and reason are false statements