Explore topic-wise InterviewSolutions in Current Affairs.

Two rods each of length $L_2$ and coefficient of linear expansion ${\alpha }_2$ each are connected freely to a third rod of length $L_1$ and coefficient of expansion ${\alpha }_1$ to form an isosceles triangle. The arrangement is supported on a knife-edge at the midpoint of $L_1$ which is horizontal. What relation must exist between $L_1$ and $L_2$ so that the apex of the isosceles triangle is to remain at a constant height from the knife edge as the temperature changes.

Three large plates $\text{A}$, $\text{B}$ and $\text{C}$ are placed parallel to each other and charges are shown in the figure. The charge that appears on left surface of plate $\text{B}$ is

70 calories of heat are required to raise the temperature of 2 moles of an ideal gas at constant pressure from ${30}^{\circ }Cto{35}^{\circ }C$. The amount of heat required to raise the temperature of same gas through the same range (${30}^{\circ }Cto{35}^{\circ }C$) at constant volume (R = 2 cal/mol/K)

The percentage increase in magnetic field, when the space within a current carrying toroid is filled with aluminium. The susceptibility of aluminium is $2.1\times {10}^{-5}$.

A particle free to move along the x-axis has potential energy given by $U\left(x\right)=k[1-exp(-x{)}^2]$ for $-\infty \le x\le +\infty$, where k is a positive constant of appropriate dimensions. Then

Consider the figure.

The charge appearing on $C_2$ is

A proton and an $\alpha$ - particle (Helium nucleus) enters a uniform magnetic field with their direction of velocity perpendicular to the direction of magnetic field.



$\left(iv\right)$ If proton and $\alpha$ - particle enter the magnetic field, perpendicular to it with same kinetic energy, then the ratio of the radii of curvature of proton and $\alpha$ - particle will be



​​​​​​​$[$1 Mark$]$

A train of mass ${10}^4\text{kg}$ rounds a curve of radius $100\text{m}$ at a speed of $10\text{m/s}$. At what angle the track be banked in order to have no thrust on the rails? ($g=10{\text{m/s}}^2$)

A
Rowland ring of mean radius 15 cm has 3500 turns of wire wound on a
ferromagnetic core of relative permeability 800. What is the magnetic
field B in
the core for a magnetising current of 1.2 A?

A source S and a detector D are placed at a distance d apart. A big cardboard is placed at a distance $\sqrt{2}d$ from the source and the detector as shown in figure (16-E2). The source emits a wave of wavelength = $\frac{d}{2}$ which is received by the detector after reflection from the cardboard. It is found to be in phase with the direct wave received from the source. By what minimum distance should the cardboard be shifted away so that the reflected wive becomes out of phase with the direct wave ?

Which of the following options correctly represent the $FBD$ of the block for the figure shown?

For a given gas at $1\text{atm}$ pressure, $rms$ speed of the molecules is $200\text{m/s}$ at ${127}^{\circ }\text{C}$. At $2\text{atm}$ pressure and at ${227}^{\circ }\text{C}$, the $rms$ speed of the molecules will be

The position-time graph of a body of mass $2\text{kg}$ is as given in figure. What is the impulse on the body at $t=4\text{s}$?

At certain place on railway track, the radius of curvature of railway track is $200\text{m}$. If the distance between the rails is $1.6\text{m}$, and the outer rail is raised by $0.08\text{m}$ above the inner rail, find the speed of train for which there is no side pressure of the rails.

(Take $g=10{\text{m/s}}^2$)

By what percentage should the pressure of a given mass of a gas be increased so as to decrease its volume by $20\%$ at a constant temperature?

A particle is moving along a circular path with a constant speed of $10\text{m/s}$. Find the magnitude of change in velocity of the particle when it moves through an angle of ${60}^{\circ }$ around the centre of the circle.

The capacitance of a parallel plate capacitor does not depend upon

Van der Waal’s constant “b” is a measure of

In $YDSE$ shown in the Figure, a parallel beam of light is incident on the slits from a medium of refractive index $n_1$. The wavelength of light in the medium is ${\lambda }_1$. A transparent slab of thickness $t$ and refractive index $n_3$ is put in front of one slit. The refractive index of the medium between the beam and the plane of the slits is $n_2$. The phase difference between the light waves reaching point $O$ (symmetrical, relative to the slit) is

According to einstein formula

M= m_{​​​​​​0^{/(1- v2/c2 ). As the body speeds up the mass will be greater.}}

^{_{so does that mean mass is not lost instead accumulated when a body speed up?}}

The ratio of the wavelengths of the longest wavelength lines in the Lyman and Balmer series of hydrogen spectrum is

If the radius of earth shrinks by $1.5\%$ (mass remaining same), then the value of acceleration due to gravity changes by

Two wires of length $l$, radius $r$ and length $2l$, radius $2r$ respectively having same young's modulus are hung with a weight $mg$ as shown in figure. The net elongation is

The mass and diameter of a planet have twice the value of the corresponding parameters of earth.
Acceleration due to gravity on the surface of the planet is

A 1cm long string vibrates with fundamental frequency of 256 Hz. If the length is reduced to $\frac{1}{4}cm$ keeping the tension unaltered, the new fundamental frequency will be (in Hz) (string is fixed at both ends)

A neutral point is obtained at the centre of a vertical circular current carrying coil. The angle between the plane of the coil and the magnetic meridian is

Figure
9.11 shows the strain-stress curve for a given material. What are (a)
Young’s modulus and (b) approximate yield strength for this
material?

The reverse breakdown voltage of a Zener diode is $5.6V$ in the given circuit.

The current $I_Z$ through the Zener is

A cubical block of side $0.5\text{m}$ floats on water with $30\%$ of its volume under water. What is the maximum weight that can be put on the block without fully submerging it under water?

[Take density of water $={10}^3{\text{kg/m}}^3$]

A toy car travels in a horizontal circle of radius $2a$. It is kept on the track by a radial elastic string of unstretched length $a$. The period of rotation of the toy car is $T_0$. Now, the toy car is speeded up until it is moving in a circle of radius $3a$. Assuming that the string obeys Hooke's law, find the new period $T$ in terms of $T_0$.

A long structural column (length =L) with both ends higged is acted upon by an axial compressive load P. The differential equation governing the bending of column is given by

$EI\frac{d^{2}y}{d{x}^2}=-Py$

where y is the structural lateral deflection and EI is the flexural rigidity The first critical load on column responsible for its buckling is given by

A monoatomic ideal gas, initially at temperature $T_1$ is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature. $T_2$ by releasing the piston suddenly. If $L_1$ and $L_2$ are the lengths of the gas column before and after expansion respectively, then $\frac{T_1}{T_2}$ is given by

A plane mirror is placed at the origin so that the direction ratios of its normal are $(1,-1,1).$ A ray of light, coming along the positive direction of the $x-$axis strikes the mirror. Then the direction cosines of the reflected ray are