Explore topic-wise InterviewSolutions in Current Affairs.

A solid sphere of mass $7\text{kg}$ rolls without slipping on an inclined plane of inclination ${60}^{\circ }$. What should be the minimum coefficient of static friction to support pure rolling?

When a wave travel from one to another medium what is the relation between amplitude and velocity?

The coefficient of linear expansion of of a crystal in one direction is _a1 and in every direction perpendicular to is a2. The coefficient of cubical expansion is:

Please explain briefly

When a 4.7 F capacitor is connected to a 1 kHz source, what is its capacitive reactance?

There are $n_1$ photons of frequency ${\gamma }_1$ in a beam of light. In an equally energetic beam, there are $n_2$ photons of frequency ${\gamma }_2$ . Then the correct relation is

Two balls $A$ and $B$ of the same size are dropped from the same point under gravity. If the air resistance acting on both the balls is same and the mass of $A$ is greater than the mass of $B$, then

Two blocks $A$ and $B$ each of equal mass $m$ are released from the top of a smooth fixed wedge as shown in figure. Find the magnitude of acceleration of $COM$ of the two blocks.

ABC is an equilateral triangle. Charges +q are placed at each corner. The electric intensity at O will be

The speed of sound as measured by a student in the laboratory on a winter day is 340 m s${}^{-1}$ when the room temperature is 17${}^{\circ }$ C. What speed will be measured by another student repeating the experiment on a day when the room temperature is 32${}^{\circ }$ C?

When a shell was following a parabolic path in the air, it explodes somewhere

The maximum wavelength of radiation that can produce photoelectric effect in a certain metal is 200 nm. The maximum kinetic energy acquired by electron due to radiation of wavelength 100 nm will be

The de Broglie wavelength of a tennis ball of mass 50 g moving with a velocity of 10 m/s is approximately

Angular velocity of a particle is $\omega =\frac{{\theta }^2}{2}$, where $\theta$ is angular position of particle. Tangential acceleration of particle when it has covered $1$ revolution in a circle of radius $2\text{m}$ is

When a ball is allowed to fall from a height of 20 m, 40% of its energy is lost due to impact. After one impact the ball will go up to a height of

If the length of a closed organ pipe is 1.5 m and velocity of sound is 330 m/s,

then the frequency for the second note is

[CBSE PMT 2002]

The current gain of a common emitter (CE) amplifier is 74. The emitter current is 5 mA. What is the collector current flowing in the CE amplifier?

A disc rotating about its axis and starting from rest acquires an angular speed of 100 revolutions per second in 4 s. Find the angle rotated by it during this duration.

The minimum audible wavelength at room temperature is about

[AFMC 1996]

The radius of a soap bubble is increased from $\frac{1}{\sqrt{\pi }}$ cm to $\frac{2}{\sqrt{\pi }}$cm If the surface tension of water is 30 dynes per cm, then the work done will be

Plot the acceleration - time graph of the velocity - time graph given in the figure.

Find the charges on the three capacitors connected to a battery as shown in figure (31-E1). Take $C_1=2.0\mu F,C_2=4.0\mu F,C_3=6.0\mu F$ and $V=12$ volts.

A car starts from rest and moves with uniform acceleration$a$ on a straight road from time$t=0tot=T$. After that, a constant deceleration brings it to rest. In this process the average speed of the car is

A projectile is aimed at a mark on a horizontal plane through the point of projection and calls 6 m short when its elevation angle is ${30}^0$. The projectile overshoots the mark by 9 m when the angle of projection is ${45}^0$. The correct distance of the mark is

The force on a particle is directed along an $x$ axis and given by
$F=F_0(x/x_0-1).$ Find the work done by the force in moving the particle from $x=0$ to $x=2x_0$.

When a fast electron passes near a highly positively charged nucleus, x-rays are seen to get radiated. What could be the cause for this radiation?

One end of a nylon of length $4.5m$ and diameter $6mm$ is fixed to a tree-limb. A monkey weighing $100N$ jumps very slowly to catch the rope and stays there. Find the change in the diameter of the rope. Young’s modulus of nylon $=4.8\times {10}^{11}N{m}^{-2}$ and Poisson’s ratio of nylon $=0.2$.

The radioactive sources $A$ and $B$ of half lives of $2\text{hr}$ and $4\text{hr}$ respectively, initially contain the same number of radioactive atoms. At the end of 2 hours, their rates of disintegration are in the ratio :

A capacitance of $2\mu F$ is required in an electrical circuit across a potential difference of $1.0kV$. A large number of $1\mu F$ capacitors are available which can withstand a potential difference of not more than $300V$. The minimum number of capacitors required to achieve this is

The angular momentum of an electron in the hydrogen atom is $\frac{3h}{2\pi }$. Here $h$ is planck's constant. The kinetic energy of this electron is

The maximum electric field strength E due to a uniformly charged ring of radius r, happens at a distance x, where value of x is (x is measured from the centre of the ring)

Two long parallel wires P and Q are both perpendicular to the plane of the paper with distance 5m between them. If P and Q carry current of 2.5A and 5A respectively in the same direction, then the magnetic field at a point halfway between the wires is:

A transparent cube of 15cm edge contains a small air bubble. Its apparent depth when viewed through one face is 6cm and when viewed through the opposite face is 4cm. Then, the refractive index of the material of the cube is:

A body of mass $m=2\text{kg}$, initially at rest and sliding along a frictionless track from a height $\text{h}$ (as shown in the figure) just completes a vertical circle of diameter $\text{AB= 3 m}$. The height $\text{h}$ is equal to

An oscillating mass spring system has a mechanical energy 1 joule, when it has an amplitude 0.1m and maximum speed of 1$m{s}^{-1}$. Then the force constant of the spring is

A tuning fork $A$ of unknown frequency produces $4$ beats per second when sounded with another tuning fork $B$ of frequency $254\text{Hz}$. When tuning fork $A$ is loaded with wax, it still gives $4$ beats per second with tuning fork $A$. The initial unknown frequency of tuning fork $A$ is

Let $\overrightarrow{a}=i+2j+k,\overrightarrow{b}=i-j+kand\overrightarrow{c}=i+j-k,$ a vector in the plane $\overrightarrow{a}and\overrightarrow{b}$ whose projection on $\overrightarrow{c}is\frac{1}{\sqrt{3}}is........$

Amplitude modulation has

Figure shown a liquid of density $1200kg{m}^{-3}$ flowing steadily in a tube of varying cross section, the cross-section at a point A is 1.0 cm2 and that at B is $20m{m}^2$. The point A and B are in the same horizontal plane. The speed of the liquid at A is 10 cm/s. Calculate the difference in pressure at A and B.

A sphere of radius 1m and refractive index 1.5 is silvered at its back. A point object is kept at a distance of 1 m from the front face as shown in figure. What is the position of final image w.r.t. P?