Explore topic-wise InterviewSolutions in Current Affairs.

A current of I ampere flows along an infinitely long straight thin walled hollow metallic cylinder of radius r. The magnetic field at any point outside the cylinder at a distance x form the axis is

The resistivity of potentiometer wire is ${10}^{-7}\Omega m$ and its area of cross-section is ${10}^{-6}{m}^2$. When a current $i=0.1A$ flows through the wire, its potential gradient is

Two particles $A$ and $B$ are moving on two concentric circles of radii $R_1$ and $R_2$ with equal angular speed $\omega$. At $t=0$, their positions and direction of motion are shown in the figure. The relative velocity $\overrightarrow{v_A}-\overrightarrow{v_B}$ at $t=\frac{\pi }{2\omega }$ is given by:

A cyclotron in which protons are accelerated has a flux density of $1.57\text{T}$. The frequency of variation of electric field is

In the given figure, the position - time graph of a particle of mass $0.1\text{kg}$ is shown. The magnitude of impulse at $t=2$ sec is:

A water cooler of storage capacity $120\text{litres}$ can cool water at a constant rate of $P$. In a closed circulation system (as shown schematically in this figure), the water from the cooler is used to cool an external device that constantly generates $3\text{kW}$ of power (thermal load). The temperature of the water fed into the device cannot exceed ${30}^{\circ }\text{C}$ and the entire $120\text{litres}$ of water is initially cooled to ${10}^{\circ }\text{C}$. The entire system is thermally insulated. The minimum value of $P$ for which the device can be operated for 3 hours (taking the specific heat capacity of water $=4.2{\text{kJ kg}}^{-1}{\text{K}}^{-1}$ and the density of water $=1000{\text{kg m}}^{-3})$ is

A wire loop is placed in a region of time varying magnetic field which is oriented orthogonally to the plane of the loop as shown in the figure.
The graph shows the magnetic field variation as the function of time.
Assume the positive emf is the one which drives a current in the clockwise direction and seen by the observer in the direction of B.
Which of the following graphs best represents the induced emf as a
function of time.

Two particles of masses $1\text{kg}$ and $2\text{kg}$ have displacement vectors $(7\hat{i}+2\hat{j}+3\hat{k})\text{m}$ and $(2\hat{i}+10\hat{j}+6\hat{k})\text{m}$. Find the displacement vector of the center of mass of the system.

A circular curve of highway is designed for traffic moving at $72\text{km/h}$. If the radius of the curved path is $100\text{m}$, then correct angle of banking of the road should be given by

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

The magnetic field inside a long solenoid having 50 turns $c{m}^{-1}$ is increased from 2.5 $\times {10}^{-3}$T to 2.5 T when an iron core of cross-sectional area 4 $c{m}^2$ is inserted into it. Find (a) the current in the solenoid, (b) the magnetization I of the core and (c) the Pole strength developed in the core.

The interference pattern is obtained with two coherent light sources of intensity ratio $n$. In the interference pattern, the ratio $\frac{I_{max}-I_{min}}{I_{max}+I_{min}}$ will be

A source of sound waves is travelling as shown. In which situation would the stationary observer detect the largest decrease in the observed frequency?



[Assume, medium is stationary]

A track (circular) is designed for car passing through a point with speed $72km/hr$ & radius equals to $40m$. If coefficient of friction between tyres & road is $\mu$$=0.6$, find maximum speed at which the car can turn?

Two blocks of masses $2\text{kg}$ and $5\text{kg}$ are at rest on ground. The masses are connected by a string passing over a frictionless light pulley which is under the influence of a constant upward force $F=50\text{N}$. The acceleration of $5\text{kg}$ and $2\text{kg}$ masses are

Find the tension in the string.

The following two observtions were taken for determining surface tension $T$ of waer by capillary method:

Diameter of capillary, $D=1.25\times {10}^{-2}m$ andrise of watter, $h=1.45\times {10}^{-2}m$.

Using $g=9.80m{s}^{-2}$ and thhe simplified relation, $T=\frac{rhg}{2}\times {10}^{3}N{m}^{-1}$, where $r$ is radius of capillary tueb, the maximum error in surface tension is close to

Two resistors with temperature coefficient of resistance ${\alpha }_1$ and ${\alpha }_2$ have resistance $R_1$ and $R_2$ at $0^{\circ }C$. The temperature coefficient of the compound resistor consisting of the two resistors connected in parallel

In the figure given below, four identical circular rings of mass $10\text{kg}$ and radius $1\text{m}$ each, are lying in the same plane. The moment of inertia of the system about an axis through point $A$ and perpendicular to the plane of the rings is

In a transformer, the coefficient of mutual inductance between the primary and the secondary coil is 0.2 henry. When the current changes by 5 ampere/second in the primary coil, the induced e.m.f. in the secondary coil will be

In a historical experiment to determine Planck's constant, a metal surface was irradiated with light of different wavelengths. The emitted photoelectric energies were measured by applying a stopping potential. The relevant data for the wavelength ($\lambda$) of incident light at the corresponding stopping potential ($V_0$) are given below:

Find the energy stored in the circuit containing four capacitors at the steady state.

The speed of projection of a projectile is increased by 5%, without changing the angle of projection. The percentage increase in the range will be

The amount of heat energy required to raise the temperature of $1\text{gm}$ of Helium at $\text{NTP}$, from $T_1\text{K}\text{to}{T}_2\text{K}$ is-

The value of the resistor, $R_S$, needed in the dc voltage regulator circuit shown here is equal to :