Explore topic-wise InterviewSolutions in Current Affairs.

A train moves towards a stationary observer with speed $34m/s$. The train sounds a whistle and its frequency registered is $f_1$. If the train’s speed is reduced to $17m/s$, the frequency registered is $f_2$. If the speed of sound is $340m/s$ then the ratio $\frac{f_1}{f_2}$ is

Equation of state for a gas is given by $P(V-b)=nRT$. If 1 mole of gas is isothermally expanded from volume V to 2V, then total work done during that process is

A mass $m$ is suspended from a spring of spring constant $K$ and just touches another identical spring fixed to the floor as shown in the figure. The time period of small oscillations is

How is a Zener diode fabricated? What causes the setting up of high electric field even for small reverse bias voltage across the diode?

Describe, with the help of a circuit diagram, the working of Zener diode as a voltage regulator

OR

(a) Explain with the help of a diagram, how depletion region and potential barrier are formed in a junction diode.

(b) If a small voltage is applied to a p-n junction diode, how will the barrier potential be affected when it is (i) forward biased, and (ii) reveres biased?

Figure shows the variation of the moment of inertia of a uniform rod, about an axis passing through its centre and inclined at an angle $\theta$ to the length. The moment of inertia of the rod about an axis passing through one of its ends and making an angle $\theta =\frac{\pi }{3}$ is ( Take the figure to be a part of sine curve)

A particle moves with a velocity $\overrightarrow{v}=(7\hat{i}-5\hat{j}+6\hat{k})m{s}^{-1}$ under the influence of a constant force $\overrightarrow{F}=(10\hat{i}+10\hat{j}+20\hat{k})N$. The instantaneous power applied to the particle is

A container has two immiscible liquids of densities ${\rho }_1$ and ${\rho }_2(>{\rho }_1)$. A capillary tube of radius $r$ is inserted in the liquid so that its bottom reaches upto the denser liquid. The denser liquid rises in the capillary and attains a height $h$ from the interface of the liquids, which is equal to the column length of the lighter liquid. Assuming angle of contact to be zero, the surface tension of heavier liquid is

Two identical rods each of mass 'M' and length 'l' are joined in crossed position. The moment of inertia of this system about a bisector is.

Two parallel-plate capacitors of capacitance $C$ and $2C$ are connected in parallel and charged to a potential difference $V$. The battery is then disconnected and the region between the plates of capacitor $C$ is filled completely with a material of dielectric constant $K$. The common potential difference across the combination becomes

In a given circuit as shown the two input waveform A and B are applied simultaneously. The resultant waveform Y (in shape) is

Four charges, all of the same magnitude, are placed at the four corners of a square. At the centre of the square, the potential is V and the field is E. By suitable choices of the signs of the four charges, which of the following can be obtained –

On forgetting his 25th anniversary, Vijay as a present from his wife, receives a shoe of 0.5 kg thrown at him with 10 m/s velocity. Find the momentum of assault.

A particle of mass $m$ begins to slide down a fixed smooth sphere from the top as shown. What is its acceleration when it breaks off the sphere?

What is the dimensional formula of angular momentum $L$ ?
$L=rp\sin \theta$, where $r$ is the position and $p$ is momentum.

Ship $\text{A}$ is sailing towards north-east with velocity vector $\overrightarrow{v}=30\hat{i}+50\hat{j}\text{km/hr}$ where $\hat{i}$ points east and $\hat{j}$ north. Ship $B$ is at a distance of $80\text{km}$ east and $150\text{km}$ north of Ship $A$ and is sailing towards west at $10\text{km/hr}$. $A$ will be at minimum distance from $B$ in,

A person measures the time period of a simple pendulum inside a stationary lift and finds it to be T . If the lift starts accelerating upwards with an acceleration g/3, the time period of pendulum will become

A smooth inclined plane is inclined at an angle $\theta$ with the horizontal. A body starts from rest and slides down the inclined surface, then the time taken by the body to reach the bottom is:

Three blocks $A,B$ and $C$ of equal mass $m$ are placed on a smooth surface as shown. Coefficient of friction between any two blocks of $A,B$ and $C$ is $\mu$. The maximum value of mass $D$ so the block $A,B\&C$ move without slipping over each other is

A ray of light travelling in transparent medium of refractive index $\mu$ falls on a surface separating the medium from air at an angle of incidence of ${45}^{\circ }$. For which of the following value of $\mu$ the ray can undergo TIR?

A stationary $P{b}^{200}$ nucleus emits an alpha-particle with kinetic energy $T_{\alpha }$. The fraction of recoil energy of the daughter nucleus to the total energy liberated is :

If $\overrightarrow{A}=3\hat{i}+6\hat{j}and\overrightarrow{B}=\hat{i}+4\hat{j}$ , what angle does ($\overrightarrow{A}-\overrightarrow{B}$ ) make with positive x-axis?

For the system shown in the given figure, the surface on which the blocks are placed is smooth. If the two blocks are displaced by small amount, then determine the time period of oscillation of resulting motion of two blocks.

A phonograph record of radius R, which carries a uniformly distributed charge Q, is rotating with constant angular speed $\omega$ figure. Find the magnetic field at the center of the disk.

Velocity time graph of a particle of mass 3 Kg moving in a straight line in shown in the figure. The work done by all the forces acting on the particle in a time t = 3s is

A body is hanging over a pulley inside a car through a string. The second end of the string is in the hand of a person standing in the car. The car is moving with constant acceleration $a$ directed horizontally as shown in figure. Other end of the string is pulled with constant acceleration $a$ vertically. The tension in the string is equal to -

A particle is dropped from a height $h=100\text{m}$, from the surface of a planet. If in the last $\frac{1}{2}\text{sec}$ of its journey, it covers $19\text{m}$, the value of acceleration due to gravity on that planet is:

A body is projected along a rough horizontal surface with a velocity $6\text{m/s}$. If the body comes to rest after travelling $9\text{m}$, then coefficient of sliding friction, is $(g=10{\text{m/s}}^2)$

Motion described by an object is shown in the figure given below, the acceleration of the object is

Column I of the following table gives a list of bodies and column II gives their moments of inertia about the axis of symmetry passing through their centre of mass. Assume mass of each of the bodies is $M$. Then identify the correct matching.

A girl tosses the coin in a aeroplane that is moving at the constant speed what is the path of the coin with respect to the piolet

A copper rod of length 1.0 m is clamped at its middle point. Find the frequencies between 20 Hz and 20,000 Hz at which standing longitudinal waves can be set up the rod. The speed of sound in copper is $3.8km{s}^{-1}$.

The rest mass energy of an electron as well of an positron is 0.51 MeV. If a $\gamma$-photon of energy 2.42 MeV produces an electron – positron pair, then the kinetic energy of each particle is

A particle performs simple harmonic motion with amplitude $A$. Its speed is tripled at the instant it is at a distance $\frac{2A}{3}$ from equilibrium position. The new amplitude of the motion is

A spherical solid ball of volume V is made of a material of density $‘s_1$’. It is falling through a liquid of density $‘s_2^{\prime }(s_2<s_1)$ assume that the liquid applies a viscous force on the ball that is proportional to the square of its speed ‘v’, $F_{viscous}=K\cdot v^2$, The terminal speed of the ball is

The angle which the bicycle and its rider must make with the vertical when going round a curve of $8.1\text{m}$ radius at $9m{s}^{-1}$ is (Take $g=10m/s^2$)

A particle executing SHM has maximum acceleration of $2\pi {\text{m/s}}^2$ and maximum velocity of $6\text{m/s}$. Find its time period of vibration

Find the maximum force $F$ to be applied for the system shown, so that the two blocks move together. Take $g=10{\text{m/s}}^2$.

I have studied that power= force × velocity

But how can a body applied by a force will have a constant velocity? Shouldn't it accelerate? Why is this violating the basic newtons laws

A 200g golf ball is moving with a speed of $5m$ per hour. The associated wave length is ball is moving with a speed of $5m$ per hour. The associated wave length is

The vertical height of the projectile at time $t$ is given by $y=4t-5t^2$ and the horizontal distance covered is given by $x=3t$ where $x$ and $y$ are in $\text{m}$ and $t$ in $\text{s}$. What is the angle of projection with the horizontal?

Moment of inertia of a uniform rod $AB$ about axis $Y{Y}^{\prime }$ as shown in figure is

A network consisting of three resistors, three batteries, and a capacitor is shown in the figure


$\begin{array}{ccc}& \text{Column I}& \text{Column II}\\ \left(A\right)& \text{Current in branch EB is}& \text{(P)}10\mu C\\ \left(B\right)& \text{Current in branch CB is}& \text{(Q)}0.5\mu C\\ \left(C\right)& \text{Current in branch ED is}& \text{(R)}1.5\mu C\\ \left(D\right)& \text{Charge on capacitor is}& \text{(S)}5\mu C\\ & & \text{(T)}7.5\mu C\end{array}$
Which of the following option has the correct combination considering column - I and Column - II.

The velocity at the maximum height of a projectile is $\frac{\sqrt{3}}{2}$ times its initial velocity of projection $\left(u\right)$. Its range on the horizontal plane is

The force required to keep a body in uniform circular motion is

The rod is released. What is the angular speed when it turns by ${180}^o$?

Two rods of length $L_1$ and $L_2$ are welded together to make a composite rod of length $(L_1+L_2)$. If the coefficients of linear expansion of the rod are ${\alpha }_1$ and ${\alpha }_2$ respectively, the effective coefficient of linear expansion of the composite rod will be

In the figure shown, find the direction of friction on $A$ and $B$ respectively on the surface, which is in contact with the surface of block $A$.

A transformer has 50 turns in the primary and 100 in the secondary. If the primary is connected to a 220 V DC supply, what will be the voltage across the secondary ?