Explore topic-wise InterviewSolutions in Current Affairs.

A rocket with a lift-off mass 20,000 kg is blasted upwards with an initial acceleration of $5.0m{s}^{-2}$. Calculate the initial thrust (force) of the blast.

A car travels from $A$ to $B$ at a speed of $10\text{km/hr}$ and returns at a speed of $30\text{km/hr}$. The average speed of the car for the whole journey is

If $\overrightarrow{r}.\hat{i}=\overrightarrow{r}.\hat{j}=\overrightarrow{r}.\hat{k}$ and $|r|=2$, then find $\overrightarrow{r}$.

A bullet of mass $20\text{g}$ and moving with $600\text{m/s}$ collides with a block of mass $4\text{kg}$ hanging with the string. What is velocity of bullet when it comes out of block, if block rises to height $0.2\text{m}$ after collision?
(Take $g=10{\text{m/s}}^2$)

An engineer has designed a road with a curve of radius $12\text{m}$. The material of the road offers a maximum coefficient of friction of $0.3$. What should be the maximum permissible speed limit on this road?

Evaluate Rydberg constant by putting the values of the fundamental constants in its expression.

A ball falls on the ground from a height of $2.0\text{m}$ and rebounds up to a height of $1.5\text{m}$. Find the coefficient of restitution for the collision of the ball with the ground. Take $g=10{\text{m/s}}^2$.

If Y = A Sin ( wt- kx ) find dimension of w and k if Y is displacement, x is distance and t is time.

A circular loop of string rotates about its axis on a frictionless horizontal plane at plane at a uniform rate so that the tangential speed of any particle of the string is v. If a small transverse disturbance is produced at a point of the loop, with what speed (relative to the string) will this disturbance travel on the string ?

$\sqrt{12+\sqrt{12+\sqrt{12+......}}}$ is equal to

The internal resistance of a battery cannot be measured with a conventional multimeter

The period of a satellite in a circular orbit of radius R is T, the period of another satellite in a circular orbit of radius 4R is

A solid sphere of mass M and radius R having a moment of inertia I about its diameter is recast into a solid disc fo radius r and thickness t. The moment of inertia of the disc about an axis passing the edge and perpendicular to the plane remains I. Then R and r are related as

When a ball is thrown up vertically with velocity $V_0,$ it reaches a maximum height of '$h$'. If one wishes to triple the maximum height then the ball should be thrown with velocity. (AIIMS 2005)

Does a short wire require large force to break than long wire why

A drop of liquid of diameter 2.8 mm breaks up into 125 identical drops.

The change in energy is nearly (S.T. of liquid =75 dynes/cm)

A ball is thrown vertically upwards attains a maximum height of 45m. What is the time after which velocity of the ball become equal to half the velocity of projection?

A gas in an airtight container is heated from ${25}^{o}C$ to ${90}^{o}C$. The density of the gas will

A wire 40 cm long carries a current of 20 A. It is bent into a loop and placed with its plane perpendicular to a magnetic field having a flux density of 0.52 T. What is the torque on the loop if it is bent into a square.

The capacitor plates are fixed on an inclined plane and connected to a battery of e.m.f. $E$. The capacitor plates have area $A$, length $l$ and the distance between them is $d$. A dielectric slab of mass $m$ and dielectric constant $k$ is inserted into the capacitor and tied to a mass $M$ by a massless string as shown in the figure. Find the value of $M$ for which the slab will stay in equilibrium. There is no friction between slab and plates.

Two wires of different densities but same area of cross section are sodered together at one end and are stretched to a tension T. The velocity of a transverse wave in the first wire is double of that in the second wire. Find the ratio of the density of the first wire to that of the second wire.

In the given figure a block of mass M and density $\rho$ is immersed in liquid of density $\sigma$. The block is attached to the spring from top and string from bottom. Elongation in the spring when string is tight is x and spring constant is $\frac{Mg}{3x}$.

$\begin{array}{cccccc}& Column1& & Column2& & Column3\\ & & & \left(Tensiondevelopedinstring\right)& & \left(Forcegeneratedinspring\right)\\ \left(I\right)& If\rho =2g/cc& \left(i\right)& T=\frac{4Mg}{3}& \left(P\right)& F=\frac{Mg}{3}\\ & \sigma =1g/cc& & & & \\ \left(II\right)& If\rho =1g/cc& \left(ii\right)& T=\frac{Mg}{3}& \left(Q\right)& F=0\\ & \sigma =1g/cc& & & & \\ \left(III\right)& If\rho =1g/cc& \left(iii\right)& T=\frac{Mg}{2}& \left(R\right)& F=\frac{Mg}{2}\\ & \sigma =2g/cc& & & & \\ \left(IV\right)& If\rho =1.2g/cc& \left(iv\right)& T=0& \left(R\right)& F=\frac{4Mg}{3}\\ & \sigma =0.8g/cc& & & & \end{array}$
Mark the incorrect combination.

Hubble telescope uses mean wavelength $\lambda =550nm.$ Aperture of objective is $12.2m$. It is established at a distance $570km$ from Earth. Find the smallest size of crater that can be identified in image by telescope.

Diameter of steel rod fixed between two rigid supports is $20\text{mm}$. Find the stress in the rod when the temperature increases by ${80}^{\circ }\text{C}$.
$($Take Young's modulus, $Y=2\times {10}^{11}{\text{N/m}}^2$ and thermal expansion coefficient ,$\alpha =12\times {10}^{-6}/{}^{\circ }\text{C})$

A recording disc rotates steadily at $45rpm$ on a table. When a small mass of $0.02kg$ is dropped gently on the disc at a distance of $0.04m$ from its axis, it gets stuck to the disc and the rate of revolution falls to $36rpm$. The moment of inertia of the disc about its centre is

A vessel of volume 125 $c{m}^3$ contains tritium ${(}^{3}H,t_{\frac{1}{2}}$ = 12.3 y) at 500 kPa and 300 K. Calculate the activity of the gas.

A block of mass $2.0\text{kg}$ is moving on a frictionless horizontal surface with a velocity of $1.0\text{m/s}$ as shown in figure, move towards another block of equal mass at rest. The spring constant of the spring fixed at one end is $100\text{N/m}$. Find maximum compression of the spring.

An aircraft with a wingspan of 40 m flies with a speed of 1080 km / hr in the eastward direction at a constant altitude in the northern hemisphere, where the vertical component of the earth’s magnetic field $1.75\times {10}^{-5}T$. Then the emf developed between the tips of the wings is

A projectile is required to hit a target whose co-ordinates relative to horizontal and vertical axes through the point of projection are $(\alpha ,\beta )$. If the gun velocity is $\sqrt{2g\alpha }$. Then the condition when it is impossible to hit the target.

The dispersion of white light when it passes through a prism shows that:

In the figure shown, what minimum force $‘F^{\prime }$ should be applied perpendicular to the top face of the block for it to not move? Given the coefficient of static friction between the plane and the block $=0.5$. Take $g=10{\text{m/s}}^2$

Two coaxial circular loops are shown in figure, smaller loop (radius = r) is at distance x above the larger one (Radius = R) with x >> R. Now if x is changing at a constant rate $\frac{dx}{dt}$ = v > 0 and current is flowing in the larger loop as shown then :

What amount of heat will be generated in a coil of resistance R due to a charge q passing through it, if the current in the coil decreases down to zero uniformly during a time interval $\Delta$ t?

Photoelectric effect experiments are performed using three different metal plates p,q and r having work functions ${\varphi }_p=2.0eV,{\varphi }_q=2.5eVand{\varphi }_r=3.0eV$, respectively. A light beam containing wavelengths of 550 nm, 450 nm and 350 nm with equal intensties illuminates each of the plates. The correct I-V graph for the experiment is (IIT-JEE-2009)

A marble block of mass $2kg$ lying on the ice, when given a velocity of $6m/s$ is stopped by friction in $10s$. Then find the value of the coefficient of friction if $g=10m/s^2$.

Two particles P and Q describe S.H.M. of same amplitude and same frequency f along the same straight line. The maximum distance between the two particles is $a\sqrt{2}$. The phase difference between the particles is :

Two equal discs are in contact on a table. A third disc of same mass but of double radius strikes them symmetrically and remains at rest after impact. The co-efficient of restitution is:

On a cold winter day, the atmospheric temperature is $-\theta$ (on Celsius scale) which is below $0^{\circ }\text{C}$. A cylindrical drum of height $h$ made of a bad conductor is completely filled with water at $0^{\circ }\text{C}$ and is kept outside without any lid. Calculate the time taken for the whole mass of water to freeze. Thermal conductivity of ice is $K$ and its latent heat of fusion is $L$. Neglect expansion of water on freezing.

A body moves a distance of $10\text{m}$ along a straight line under the action of a force $5\text{N}$. If the work done is $25\text{joule}$, the angle which the force makes with the direction of motion of body is: