Explore topic-wise InterviewSolutions in Current Affairs.

The light rays having photons of energy 1.8 eV are falling on a metal surface having a work function 1.2 eV. What is the stopping potential to be applied to stop the emitting electrons

A person wants to roll a solid non-conducting spherical ball of mass m and radius r on a surface whose coefficient of static friction is $\mu$ . He placed the ball on the surface wrapped with n turns of closely packed conducting coils of negligible mass at the diameter. By some arrangement he is able to pass a current i through the coils either in the clockwise direction or in the anti-clockwise direction. A constant horizontal magnetic field B is present throughout the space as shown in the figure. (Assume $\mu$ is large enough to help rolling motion)


The minimum va­lue of $\mu$ for which the rolling motion is possible, is

A car is moving in direction $\overrightarrow{r}=-4\hat{i}+3\hat{j}$ with a speed of 10m/s. Write velocity vector of car in vector notation.

Why in umbrella example of relative velocity we find angle made by y axis not by x axis

A car of mass $1000\text{kg}$ negotiates a banked curve of radius $90\text{m}$ on a frictionless road. If the banking angle is ${45}^{\circ }$, the speed of car is (Take $g=10{\text{m/s}}^2$)

The fastest limit at which a vehicle is permitted to drive on a road is known as its _____.

A projectile is thrown with an initial velocity of $(x\hat{i}+y\hat{j})\text{m/s}$. If the range of the projectile is double the maximum height reached by it, then

Percentage change in moment of inertia of a solid body when temperature is changed by ${50}^{\circ }\text{C}$ is
$[{\alpha }_{\text{body}}=12\times {10}^{-6}{/}^{\circ }\text{C}]$

Which of the following will be the dimensions of $\frac{a}{b}$ in the relation
$P=\frac{a-t^2}{bx}$ , where $P$ is the pressure, $x$ is the distance and $t$ is the time?

The motion of a car along Y axis is given by the relation y= t^3-6t^2+9t+5. Y is in metres and t is in sec.calculate the position,velocity and acceleration at t=5 sec and distance travelled during 0 to 5 sec

the uncertainty in the position of an electron is zero, the uncertainty in its momentum be

A car of mass $1000\text{kg}$ moves in a circular path with a constant speed of $16\text{m/s}$. It is turned by ${90}^{\circ }$, while travelling a distance of $628\text{m}$ on the road. The centripetal force acting on the car is

An object of mass 0.2 kg executes simple harmonic motion along X-axis with frequency of 25/ $\pi$ Hz. At the position x = 0.04 m, the object has kinetic energy of 0.5 J and potential energy of 0.4 J. The amplitude of oscillation in meter is equal to

A die is thrown 100 times. Getting an even number is considered as a success , the variance of number of successes is

How high does the ball go?

A rod of length $L$ is pivoted at one end and is rotated with a uniform angular velocity in a horizontal plane. The value of $x$ for point $P$, where tension is ${\left(\frac{1}{4}\right)}^{th}$ of the tension at $O$

Which takes more time - attracting a charge of opposite polarity or attracting a neutral body?

The photoelectric threshold wavelength for potassium (work function being 2eV) is

A uniformly tapering vessel is filled with a liquid of density 900 $kg/m^3$. The force that acts on the base of the vessel due to the liquid is (g=$10m{s}^{-2}$)

$heightofthevessel=0.4m$ $,Areaofthebottomofthevessel=2\times {10}^{-3}m$

The series limit for Balmer series of hydrogen spectra is

​​​​​​Please explain the question and answer accordingly.

A body of mass $2\text{kg}$ initially at rest moves under the action of an applied horizontal force of $7\text{N}$ on a table with coefficient of kinetic friction ${\mu }_k=0.1$.
Calculate the work done by kinetic friction in $10\text{sec}(g=9.8{\text{m/s}}^2)$

If $x^2$ - 6x + 11 is a factor of bi-quadratic equation $x^4$ + $x^3$- 25 $x^2$ + 41x + 66 = 0. Find the product of other factor of bi-quadratic equation and x+1.

Which of the following is the correct result if we add the given vectors?

Consider the situation in figure. The frame is made of the same material and has a uniform cross- sectional area everywhere. Calculate the amount of heat flowing per second through a cross section of the bent part if the total heat taken out per second from the end at ${100}^{\circ }C$ is 130 J.

The current in a conductor and the potential difference across its ends are measured by an ammeter and a voltmeter. The meters draw negligible currents. The ammeter is accurate but the voltmeter has a zero error (that is, it does not read zero when no potential difference is applied). Calculate the zero error if the readings for two different conditions are 1.75 A, 14.4 V and 2.75 A, 22.4 V.

The line width of a bright fringe is sometimes defined as teh separation between the points on the two sides of the central line where the intensity falls to half the maximum. Find the line- width of a bright fringe in a young's double slit experiment in terms of $\lambda$ d and D where the symbols have their usual meanings.

The coefficient of viscosity of a fluid is given by:

A U-tube is partially filled with water. Oil, which does not mix with water, is next poured into one side, until water rises by 25 cm on the other side. If the density of the oil is 0.8 g/cc, the oil level will stand higher than the water level by

Look at the drawing given in the figure which has been drawn with ink of uniform line-thickness. The mass of ink used to draw each of the two inner circles, and each of the two line segments is $m$. The mass of the ink used to draw the outer circle is $6m$. The coordinates of the centers of the different parts are: outer circle $(0,0)$ left inner circle $(-a,a),$ right inner circle $(a,a),$ vertical line $(0,0)$ and horizontal line $(0,a).$ The y-coordinate of the center of mass of the ink in this drawing is:

Two spheres made of same substance have diameters in the ratio 1 : 2. Their thermal capacities are in the ratio of

In the arrangement shown in the figure mass of the block A and body B are 2m, 8m respectively. The surface between body B and floor is smooth. The body B is connected to block C by means of pulley. If the whole system is released then the minimum value of mass of the block C so that the block A remains stationary with respect to B is (Coefficients of friction between A and B is $\mu$)

A simple pendulum is of period $T_1$. The point of suspension is moved according to $y=K{t}^2$, where y is the vertical displacement and $k=1m{s}^{-1}$. The new period is $T_2$. If $g=10m{s}^{-2},\frac{T_1^2}{T_2^2}$ at $t=1s$ is

In an electric field shown in figure three equipotential surfaces are shown. If function of electric field is $2x^2\frac{V}{m}$, and given that $V_1-V_2=V_2-V_3$ then we have

The angle between the dipole moment and electric field at any point on the equatorial plane is

An electron of mass $m_e$, initially at rest, moves through a certain distance in a uniform electric field in time $t_1$. A proton of mass $m_p$, also initially at rest takes time $t_2$to move through an equal distance in this uniform electric field. Neglecting the effect of gravity, the ratio $\frac{t_2}{t_1}$ is nearly equal to

Two solids A and B float in water. It is observed that A floats with half of its volume immersed and B floats with 2/3 of its volume immersed. Compare the densities of A and B

A cell of internal resistance $1\Omega$ is connected across a resistor. A voltmeter having variable resistance G is used to measure p.d across resistor. The plot of voltmeters reading V against G is shown. What is value of external resistor R (in ohm)?

___

A charge ‘q’ is placed at the centre of a conducting spherical shell of radius $R$, which is given a charge 'Q'. An external charge Q' is also present at distance $R^{\prime }(R^{\prime }>R)$ from ‘q’. Then the resultant electric field will be best represented for region $r$ > R by: (where $r$ is the distance of the point from q)

Assume there is one electron charge - e inside a spherical region of uniform charge density $\rho$ (a Thomson hydrogen atom). If the sphere of the radius is given to be $1.0\times {10}^{-10}m$ , the frequency of the radiation emitted by the atom is

A block of mass $m=1\text{kg}$ is at rest with respect to a rough wedge as shown.The wedge starts moving up from rest with an acceleration of $a=2{m/s}^2$ and the block remains at rest with respect to wedge. Then in 4 seconds of motion (if $\theta ={30}^{\circ }$ and $g=10{\text{m/s}}^2$) work done on block.

$\begin{array}{cccc}& \text{Column-I}& & \text{Column-II}\\ \text{(A)}& \text{By gravity (in magnitude)}& \text{(P)}& 144\text{J}\\ \text{(B)}& \text{By normal reaction}& \text{(Q)}& 32\text{J}\\ \text{(C)}& \text{By frictional force}& \text{(R)}& 160\text{J}\\ \text{(D)}& \text{By all the forces}& \text{(S)}& 48\text{J}\end{array}$
Which of the following is the only CORRECT combination?

A particle executes a simple harmonic motion of amplitude 1.0 cm along the principal axis of a convex lens of focal length 12 cm. The mean position of oscillation is at 20 cm from the lens. Find the amplitude of oscillation of the image of the particle.

Two particles A and B having equal charges +6C, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular paths of radii 2cm and 3cm, respectively. The ratio of mass of A to that of B is:

A particle a Having a charge of $2.0\times {10}^{-6}C$ and a mass of 100 g is placed at the bottom of a smooth inclined plane oif inclination ${30}^{\circ }$ Where should another particle B, having same charge and mass, be placed on the incline so that it may remain in equilibrium?

In the figure shown, all the blocks are of equal mass of $10\text{kg}$ and $F=300\text{N}$. Find the tension in the string, $T_{BC}$. Assume all surface to be smooth and $g=10{\text{m/s}}^2$.