Explore topic-wise InterviewSolutions in Current Affairs.

Ice starts forming in lake with water at $0^{\circ }C$ and when the atmospheric temperature is $-{10}^{\circ }C$. If the time taken for 1cmof ice be 7 hours, then the time taken for the thickness of ice to change from 1 cm to 2 cm is

1. 0

1. 0.58

A block of mass $2\text{kg}$ initially at rest moves under the influence of a time-dependent force $\overrightarrow{F}=4tN\hat{i}.$ The power developed by the force at $t=2\text{second}$ is

A small roller of diameter $20\text{cm}$ has an axle of diameter $10\text{cm}$ (see figure below on the left). It is on a horizontal floor and a meter scale is positioned horizontally on its axle with one edge of the scale on top of the axle (see figure on the right). The scale is now pushed slowly on the axle so that it moves without slipping on the axle, and the roller starts rolling without slipping. After the roller has moved $50\text{cm}$ , the position of the scale will look like :

(figures are schematic and not drawn to scale)

A parallel beam of light of wavelength $6000\mathring{A}$ gets diffracted by a single slit of width $0.3\text{mm}$. The angular position of the first minima of diffracted light is,

A p-type semiconductor has acceptor levels 57 $meV$ above the valence band. The maximum wavelength of light required to create a hole is (Planck's constant

h= 6.6×10-34J-s)

A heavy uniform rod is hanging vertically from a fixed support. It is stretched by its own weight. The diameter of the rod is

The
electrical resistance in ohms of a certain thermometer varies with
temperature according to the approximate law:

R = R_o
[1 + α (T –
T_o)]

The
resistance is 101.6 Ω at the triple-point of water 273.16 K,
and 165.5 Ω at the normal melting point of lead (600.5 K). What
is the temperature when the resistance is 123.4 Ω?

A block is dragged on a smooth plane with the help of a rope which moves with a velocity $v$ as shown in figure. The horizontal velocity of the block is:

A traffic policeman standing on a road sounds a whistle emitting the main frequency of 2.00 kHz. What could be the apparent frequency heard by a scooter-driver approaching the policeman at a speed of 36.0 km/h? Speed of sound in air = 340 m/s.

In a young’s double slit experiment, $D$ equals the distance of screen and $d$ is the separation between the slit. The distance of the nearest point to the central maximum where the intensity is same as that due to a single slit, is equal to

Use Lenz’s law to determine the direction of induced current in the situations described by Fig. 6.19:

(a) A wire of irregular shape turning into a circular shape;

(b) A circular loop being deformed into a narrow straight wire.

The points on the curve $y=x^3+x-2$ at which its tangents are parallel to the straight line $y=4x-1$ are :

By increasing the temperature, the specific resistance of a conductor and a semiconductor

The equation of a standing wave in a stretched string is given by $y=5\sin \left(\frac{\pi x}{3}\right)\cos \left(40\pi t\right)$, where $x$ and $y$ are in $\text{cm}$ and $t$ is in $\text{sec}$. The separation between two consecutive nodes is (in $\text{cm}$)

A long cylindrical wire of radius $a$ carries a current $i$ distributed uniformly over its cross section. If the magnetic fields at distances $r<a$ and $R>a$ from the axis have equal magnitude, then:

1. 3.68

In the arrangement shown in the figure, the ends $P$ and $Q$ of an inextensible string move downwards with uniform speed $u$. Pulleys $A$ and $B$ are fixed. What is the speed with which mass $M$ moves up?

An earth satellite has angular momentum $\alpha$ and its areal velocity about earth is $\beta$, then mass of satellite is

A block of mass $5\text{kg}$ is moving in $x-$ direction with a constant speed of $20\text{m/s}$. It is subjected to a retarding force of $F=-0.1x\text{joules/metre}$ during its travel from $x=20\text{m}$ to $x=30\text{m}$. Its final K.E. will be:

Pick the correct option - If all matter were made of electrically neutral particles such as neutrons,

A force of 50 N is applied on an area of $2m^2$. Pressure applied on the area is equal to ___Pa.

A conducting circular loop made of a thin wire, has area $3.5\times {10}^{-1}{\text{m}}^2$ and resistance $10\Omega$. It is placed perpendicular to a time dependent magnetic field $B\left(t\right)=\left(0.4\text{T}\right)\sin \left(50\pi t\right)$. The net charge flowing through the loop during $t=0\text{s}$ and $t=10\text{ms}$ is close to:

The current i in the circuit (see figure) is –

Two bodies of masses $100kgand10000kg$ are separated by distance of $1m$. The distance from the smaller body where the intensity of gravitational field is zero is

A particle of mass $m$ is dropped from a height $2R$ from the surface of the earth. The speed with which the particle hits the surface of the earth is:

Two blocks of masses $2.9\text{kg}$ and $1.9\text{kg}$ are suspended from a rigid support by two inextensible wires each of length $1\text{m}$, the upper wire has negligible mass and the lower wire has a uniform mass of $0.2\text{kg/m}$. The whole system of block, wire and support has an upward acceleration of $0.2{\text{m/s}}^2$. (take $g=9.8m/se{c}^2$)

The tension at the mid-point of lower wire is:

A particle moves
along the curve.
Find the points on the curve at which the y-coordinate
is changing 8 times as fast as the x-coordinate.

A ball is projected upwards from the top of a tower with a velocity of $50{\text{ms}}^{-1}$ making an angle of ${60}^{\circ }$ with the vertical. If the height of the tower is $70\text{m}$, then the ball will reach the ground in (Take $g=10{\text{ms}}^{-2}$)

A wheel is subjected to uniform angular acceleration about its axis. Initially
its angular velocity is zero. In the first 2 sec, it rotates through an angle ${\theta }_1$.
In the next 2 sec, it rotates through an additional angle ${\theta }_2$ . The ratio of ${\theta }_2$/${\theta }_1$ is

A glass flask is filled upto a mark with $50{\text{cm}}^3$ of mercury at ${18}^{\circ }C$. If the flask and contents are heated to ${38}^{\circ }C$, how much mercury will be above the mark?
$\alpha$ for glass is $10\times {{10}^{-6}}^{\circ }{C}^{-1}$ and coefficient of volumetric expansion of mercury is $180\times {{10}^{-6}}^{\circ }{C}^{-1}$