Explore topic-wise InterviewSolutions in .

This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

1.

An oil drop falls through air with a terminal velocity of `(5xx10^(-4))/(sec)` viscosity of air is `1.8xx10^(-5)(N-s)/(m^(2))` and density of oil is 900 kg `m^(3)` neglect density of air as compared to that of oil.A. `2.5 xx 10^(-5) m`B. `2 xx 10^(-4)`C. `3 xx 10^(-6)m`D. `4 xx 10^(-4)m`

Answer» Correct Answer - C
Discussion
2.

A spherical ball of radius `3.0xx10^(-4)` m and density `10^(4)(kg)/(m^(3))` falls freely under gravity through a distance `H=nxx500m` before entering a tank of water. If after entering the water the velocity of the ball does not change, then find n. viscosity of water is `10xx10^(-6)(N-s)/(m^(2))`,`g=10(m)/(s)`

Answer» Correct Answer - `(81)/(49) xx 10^(3) m`
`v = (2)/(9eta) r^(2).(r_(0) - r_(w))g = 180 m//sec`.
`h = (32400)/(2 xx 9.8) = (81)/(49) xx 10^(3)m`
Discussion
3.

A square brass plate of side `1.0 m` and thickness `0.0035m` is subjected to a force `F` on its smaller opposite edges, causing a displacement of `0.02 cm`. If the shear modulus o brass is `0.4 xx 10^(11) N//m^(2)`, the value on force `F` isA. `4 xx 10^(3)N`B. `400 N`C. `4 xx 10^(4)`D. `1000 N`

Answer» Correct Answer - C
`F = etaA(x)/(h) = 0.4 xx 10^(11) xx 1 xx .005 xx (.02 xx 10^(-2))/(1) = 4 xx 10^(4)N`
Discussion
4.

Find out longitudinal stress and tangential stress on a fixed block.

Answer» Logitudinal or normal stress `rArr sigma_(l) = (100sin30^(@))/(5 xx 2) = 5N//m^(2)`
Tangential stress `rArr sigma_(l) = (100cos30^(@))/(5 xx 2) = 5sqrt(3)N//m^(2)`
Discussion
5.

Find out bulk stress on the spherical object of radius `10//pi` cm if area and mass of piston are `50 cm^(2)` and `50 kg`, respectively, for a cylinder filled with gas shown in figure.

Answer» `p_(gas) = (mg)/(A) + p_(a) = (50 xx 10)/(50 xx 10^(-4)) + 1 xx 10^(5) + 1 xx 10^(5) = 2 xx 10^(5) N//m^(2)`
Bulk stress `= p_(gas) = 2 xx 10^(5)N//m^(2)`
Discussion
6.

A sphere is dropped gently into a medium of infinite extent. As the sphere falls, the force acting downwards on it.A. remain constant throughoutB. increases for sometimes and then becomes constantC. decreases for sometimes and then becomes zeroD. increases for sometime and then decreases.

Answer» Correct Answer - D
There will not be any viscous force so velocity will keep on increasing.
Discussion
7.

The terminal velocity of a sphere moving through a viscous medium is :A. directly proportional to the radius of the sphereB. inversely proportional to the radius of the sphereC. directly propotional to the square of the radius of sphereD. inversely propotional to the square of the radius of sphere

Answer» Correct Answer - C
Discussion
8.

The compressibility of water is `46.4 xx 10^(-6)//atm`. This means thatA. the bulk modulus of water is `46.4 xx 10^(6)atm`B. volume of water decrease by `46.4` one-millionths of the original volume for each atmosphere increase in pressureC. when water is subjected to an additional pressure of one atmosphere, its volume decreases by `46.4`D. when water is subjected to an additional pressure of one atmosphere, its volume decreases by `4.10^(6)` of its original volume.

Answer» Correct Answer - B
`46.4 xx 10^(-6)atm = (1)/(B)`
`B = (1)/(46.4 xx 10^(-4)) rArr B = (P)/(Deltav //v) rArr (Deltav)/(v) = (Deltap)/(B) = 46.4 xx 10^(-6)`
Discussion
9.

Two wires of the same material and length but diameters in the ratio `1:2` are stretched by the same force. The potential energy per unit volume for the two wires when stretched will be of the ratio.A. `1 : 1`B. `2 : 1`C. `4 : 1`D. `16 : 1`

Answer» Correct Answer - D
`(r_(1))/(r_(2)) = (1)/(2)`
`PE` (per unit volume) `= (1)/(2Y)((F)/(A))^(2)`
`PE prop 1//A^(2)`
`(PE_(1))/(PE_(2)) = (A_(2)^(2))/(A_(1)^(2)) = 16 : 1`
Discussion
10.

If a rubber ball is taken at the depth of 200 m in a pool, its volume decreases by`0.1%` If the density of the water is `1xx10^(3)Kg//m^(3)"and"g=10ms^(2), then the volume elasticity in N//m2 will beA. `10^(8)`B. `2 xx 10^(8)`C. `10^(9)`D. `2 xx 10^(9)`

Answer» Correct Answer - D
Discussion