Which of the following statements is correct?

1. Natural convection can occur in space having gravity as well as in gravity-free space

2. Forced convection occurs in space having gravity only

3. Forced convection can occur in gravity-free space

4. Natural convection occurs only in gravity-free space

 

The temperature of a body is raised from $20°\mathrm{C} \mathrm{to} 45°\mathrm{C}$. The rise in temperature of the body in the Fahrenheit scale is

1. $25°\mathrm{F}$

2. $77°\mathrm{F}$

3. $45°\mathrm{F}$

4. $207°\mathrm{F}$

The temperature on Celsius scale is $45°\mathrm{C}$, then corresponding temperature on the Fahrenheit scale is

1. $113°\mathrm{F}$ 

2. $77°\mathrm{F}$

3. $100°\mathrm{F}$

4. $131°\mathrm{F}$

A metal rod is placed on a smooth horizontal surface at temperature \(25^\circ ~\text{C}.\) Now temperature of the surroundings is increased up to \(100^\circ ~\text{C}\)$$, then during heating of the rod,

Given below are two statements: 
 

Given below are two statements: 
 

A faulty thermometer reads freezing point and boiling point of water as $10°C and 90°C$ respectively, the correct value of temperature as it reads $50°C$ is

(1)  $20°C$

(2) $30°C$

(3) $40°C$

(4) $50°C$

A rod of length 40 cm is stretched between two rigid supports at zero tension. If the temperature is increased by 10°C, the stress produced in it is:

(Young's modulus, Y = 1.2x${10}^{12} \mathrm{N}/{\mathrm{m}}^2$, coefficient of linear expansion of rod = 2 x ${10}^{-5}$/°C)

(1) 2.4 x ${10}^8 \mathrm{N}/{\mathrm{m}}^2$

(2) 1.2 x ${10}^8 \mathrm{N}/{\mathrm{m}}^2$

(3) 3.6 × ${10}^8 \mathrm{N}/{\mathrm{m}}^2$

(4) 4.8 x ${10}^8 \mathrm{N}/{\mathrm{m}}^2$

An aluminum rod of length 2m held fixed in a horizontal position from its one end has the other end free. When the temperature of rod increases by 100°C, the thermal stress produced in the rod will be ($\mathrm{\alpha }$ = 1.6 x ${10}^{-6}$/°C)

(1) Zero

(2) 0.08

(3) 0.1

(4) 0.4

The metal rod (Y = 2 x ${10}^{12}$ dyne/sq. cm) of the coefficient of linear expansion 1.6 x ${10}^{-5}$ per °C has its temperature raised by 20°C. The linear compressive stress to prevent the expansion of the rod is:

(1) 2.4 x ${10}^8$ dyne/sq. cm

(2) 3.2 x ${10}^8$ dyne/sq. cm

(3) 6.4 x ${10}^8$ dyne/sq. cm

(4) 1.6 x ${10}^8$ dyne/sq. cm