VITEEE 2019 :: Physics :: General questions

• Physics - General questions

The figure below shows currents in a part of an electric circuit. The current I is

Answer:

Explanation:

According to Kirchhoff's first law,

At junction A, i_AB = 2+2 = 4A

At junction B, i_AB = i_BC + 1 → i_BC = 4-1 = 3A

At junction C, i = i_BC - 1.3 = 3 - 1.3 = 1.7A

The Young's modulus of a perfectly rigid body is

Answer:

Explanation:

For a perfectly rigid body strain produced is zero for the given force applied,

So Y =  stress/strain = Infinite (∞)

A solid sphere is rotating in free space. If the radius of the sphere is increased keeping mass the same which one of the following will not be affected?

Answer:

Explanation:

Taking the same mass of sphere if the radius is increased then moment of inertia, angular velocity, and rotational kinetic energy will change but according to the law of conservation of momentum, angular momentum will not change.

A mass of 0.5 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: 50N/m. The maximum compression of the spring would be

Answer:

Explanation:

Apply the law of conservation of energy,

$\frac{1}{2}mv^{2} = \frac{1}{2}kx^{2}$

$mv^{2} = kx^{2}$ or 0.5 × (1.5)² = 50×X²

 .'. x=0.15m

Consider a pair of insulating blocks with thermal resistances R₁ and R₂ as shown in the figure. The temperature θ at the boundary between the two blocks is

Answer:

Explanation:

Rate of transmission of heat

=$\frac{Temperature difference}{Thermal resistance}$

$\frac{dQ}{dt} = \frac{d\theta}{R}$

Here, $\frac{dQ}{dt}$

= $\frac{\theta - \theta_{2}}{R_{2}} = \frac{\theta_{1}-\theta}{R_{1}}$

= $R_{1}\theta - R_{1}\theta_{2}$ = $R_{2}\theta_{1} - R_{2}\theta$

θ = $\frac{\left(R_{2}\theta_{1} + R_{1}\theta_{2}\right)}{R_{1}+R_{2}}$

• Physics - General questions