Recent questions tagged past papers

A block of mass m is placed on a smooth inclined wedge ABC of inclination $\theta$ as shown in the figure. The wedge is given as acceleration 'a' towards the right. The relation between a and $\theta$ for the block to remain stationary on the wedge is

asked Aug 21, 2018 by pady_1

1 answer

A toy car with charge q moves on a frictionless horizontal plane surface under the influence of a uniform electric field $\overrightarrow{E}$. Due to the force q $\overrightarrow{E}$, its velocity increases from 0 to 6 m/s in one second duration. At that instant the direction of the field is reversed. The car continues to move for two more seconds under the influence of this field. The average velocity and the average speed of the toy car between 0 to 3 seconds are respectively

asked Aug 21, 2018 by pady_1

1 answer

If the mass of the Sun were ten times smaller and the universal gravitational constant were ten times larger in magnitude, which of the following is not correct ?

asked Aug 21, 2018 by pady_1

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A solid sphere is rotating freely about its symmetry axis in free space. The radius of the sphere is increased keeping its mass same. Which of the following physical quantities would remain constant for the sphere?

asked Aug 21, 2018 by pady_1

1 answer

A solid sphere is in rolling motion. In rolling motion a body possesses translational kinetic energy $(K_t)$ as well as rotational kinetic energy $(K_r)$ simultaneously. The ratio $K_t : (K_t + K_r)$ for the sphere is :

asked Aug 21, 2018 by pady_1

1 answer

The kinetic energies of a planet in an elliptical orbit about the Sun, at position A, B and C are $K_A, K_B$ aand $K_C$, respectively. AC is the major axis and SB is perpendicular to AC at the position of the Sun S as shown in the figure. Then

asked Aug 21, 2018 by pady_1

1 answer

An electron falls from rest through a vertical distance h in a uniform and vertically upward directed electric field E. The direction of electric field is now reversed, keeping its magnitude the same. A proton is allowed to fall from rest in it through the same vertical distance h. The time of fall of the electron, in comparison to the time of fall of the proton is

asked Aug 21, 2018 by pady_1

1 answer

The electrostatic force between the metal plates of an isolated parallel plate capacitor C having a charge Q and area A, is

asked Aug 21, 2018 by pady_1

1 answer

A pendulum is hung from the roof of a sufficiently high building and is moving freely to and fro like a simple harmonic oscillator. The acceleration of the bob of the pendulum is $20 \; m/s^2$ at a distance of 5 m from the mean position. The time period of oscillation is :

asked Aug 21, 2018 by pady_1

2 answers

A tuning fork is used to produce resonance in glass tube. The length of the air column in this tube can be adjusted by a variable piston. At room temperture of $27^oC$ two successive resonances are produced at 20 cm and 73 cm of column length. If the frequency of the tuning fork is 320 Hz, the velocity of sound in air at $27^oC$ is

asked Aug 21, 2018 by pady_1

1 answer

An astronomical refracting telescope will have large angular magnification and high angular resolution, when it has an objective lens of

asked Aug 21, 2018 by pady_1

1 answer

In Young's double slit experiment the separation d between the slit is 2mm, the wavelength $\lambda$ of the light used is $5896 \; A^o$ and distance D between the screen and slits is 100 cm. It is found that the angular width of the fringes is $0.20^o$. To increase the fringe angular width to $0.21^o$ ( with same $\lambda$ and D ) the separation between the slits needs to be changed to

asked Aug 21, 2018 by pady_1

1 answer

Unpolarised light is incident from air on a plane surface of a material of refractive index $\mu$. At a particular angle of incidence 'i', it is found that the reflected and refracted rays are perpendicular to each other. Which of the following options is correct for this situation?

asked Aug 21, 2018 by pady_1

1 answer

In the combination of the following gates the output Y can be written in terms of inputs A and B as

asked Aug 21, 2018 by pady_1

1 answer

In a p-n junction diode, change in temperature due to heating

asked Aug 21, 2018 by pady_1

1 answer

In the circuit shown in the figure, the input voltage $V_i$ is 20 V, $V_{BE}$ = 0 and $V_{CE}$ = 0. The value of $I_B, \; I_C$ and $\beta$ are given by

asked Aug 21, 2018 by pady_1

1 answer

The refractive index of the material of a prism is $\sqrt{2}$ and the angle of the prism is $30^o$. One of the two refracting surfaces of the prism is made a mirror inwards, by silver coating. A beam of monochromatic light entering the prism from the other face will retrace its path (after reflecting from the silvered surface) if its angle of incidence on the prism is

asked Aug 21, 2018 by pady_1

1 answer

The magnetic potential energy stored in a certain inductor is 25 mJ, when the current in the inductor is 60 mA. This inductor is of inductance

asked Aug 21, 2018 by pady_1

1 answer

An em wave id propagating in a medium with a velocity $\overrightarrow{V} = V \hat{i}$. The instantaneous oscillating electric field of this em wave is along +y axis. Then the direction of oscillating magnetic field of the em wave will be along

asked Aug 21, 2018 by pady_1

1 answer

An object is placed at a distance of 40 cm from a concave mirror of focal length 15 cm. If the object is displaced through a distance of 20 cm towards the mirror, the displacement of the image will be :

asked Aug 21, 2018 by pady_1

1 answer

An inductor 20 mH, a capacitor $100 \; \mu F$ and a resistor $50 \Omega$ are connected in series across a source of emf, $V = 10 \sin 314 \;t$. The power loss in the circuit is

asked Aug 21, 2018 by pady_1

1 answer

A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from

asked Aug 21, 2018 by pady_1

1 answer

A metallic rod of mass per unit length $0.5 \; kg \; m^{-1}$ is lying horizontally on a smooth inclined plane which makes an angle of $30^o$ with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction 0.25 T is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is

asked Aug 21, 2018 by pady_1

1 answer

Current sensitivity of a moving coil galvanometer is 5 div/mA and its voltage sensitivity (angular deflection per unit voltage applied ) is 20 div/V. The resistance of the galvanometer is

asked Aug 21, 2018 by pady_1

1 answer

A set of 'n' equal resistors, of value 'R' each, are connected in series to a battery of emf 'E' and internal resistance 'R'. The current drawn is I. Now, the 'n' resistors are connected in parallel to the same battery. Then the current drawn from battery becomes 10 I. The value of 'n' is :

asked Aug 21, 2018 by pady_1

1 answer

A carbon resistor of $(47 \pm 4.7) \; k \Omega$ is to be marked with rings of different colours for its identification. The colour code sequence will be :

asked Aug 21, 2018 by pady_1

1 answer

A battery consists of a variable number 'n' of identical cells ( having internal resistance 'r' each ) which are connected in series. The terminals of the battery are short- circuited and the current I is measured. Which of the graphs shows the correct relationship between I and n ?

asked Aug 21, 2018 by pady_1

1 answer

The volume (V) of a monatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas, to the heat absorbed by it, when it undergoes a change from state A to state B, is

asked Aug 21, 2018 by pady_1

1 answer

The fundamental frequency in an open organ pipe is equal to the third harmonic of a closed organ pipe. If the length of the closed organ pipe is 20 cm, the length of the open organ pipe is :

asked Aug 21, 2018 by pady_1

1 answer

At what temperature will the rms speed of oxygen molecules become just sufficient for escapig from the Earth's atmosphere ? (Given : Mass of oxygen molecule (m) = $2.76 \times 10^{-25} kg$ Boltzmann's constant $(K_B) = 1.38 \times 10^{-23} JK^{-1}$ )

asked Aug 21, 2018 by pady_1

1 answer

The effciency of an ideal heat engine workong between the freezing point and boiling point of water, is

asked Aug 21, 2018 by pady_1

1 answer

A spring of force constant k is cut into lengths of ratio 1 : 2 : 3. They are connected in series and the new force constant is k'. Then they are connected in parallel and force constant is k''. Then k' : k'' is :

asked Aug 21, 2018 by pady_1

1 answer

The diagrams below show regions of equipotentials. A positive charge is moved from A to B in each diagram.

asked Aug 21, 2018 by pady_1

1 answer

The x and y coordinates of the particle at any time are $x = 5t – 2t^2$ and $y = 10 t$ respectively, where x and y are in meters and t in seconds. The acceleration of the particle at t = 2s is :

asked Aug 21, 2018 by pady_1

2 answers

The de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature T (Kelvin) and mass m, is :

asked Aug 21, 2018 by pady_1

1 answer

Young's double slit experiment is first performed in air and then in a medium other than air. It is found that $8^{th}$ bright fringe in the medium lies where $5^{th}$ dark fringe lies in air. The refractive index of the medium is nearly :

asked Aug 21, 2018 by pady_1

1 answer

A U tube with both ends open to the atmosphere, is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance of 10 mm above the water level on the other side. Meanwhile the water rises by 65 mm from its original level (see diagram). The density of the oil is :

asked Aug 21, 2018 by pady_1

1 answer

In an electromagnetic wave in free space the root mean square value of the electric field is $E_{rms} = 6\; V/m$. The peak value of the magnetic field is :

asked Aug 21, 2018 by pady_1

1 answer

A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watt would be :

asked Aug 21, 2018 by pady_1

1 answer

Which of the following statements are correct ? (a) Centre of mass of a body always coincides with the centre of gravity of the body. (b) Centre of mass of a body is the point at which the total gravitational torque on the body is zero. (c) A couple on a body produce both translational and rotational motion in a body (d) Mechanical advantage greater than one means that small effort can be used to lift a large load.

asked Aug 21, 2018 by pady_1

1 answer

Two discs of same moment of inertia rotating about their regular axis passing through centre and perpendicular to the plane of disc with angular velocities $\omega_1$ and $\omega_2$. They are brought into contact face to face coinciding the axis of rotation. The expression for loss of energy during this process is :

asked Aug 21, 2018 by pady_1

1 answer

Preeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time $t_1$. On other days, if she remains stationary on the moving escalator, then the escalator takes her up in time $t_2$. The time taken by her to walk up on the moving escalator will be :

asked Aug 21, 2018 by pady_1

1 answer

Two rods A and B of different materials are welded together as shown in figure. Their thermal conductivities are $K_1$ and $K_2$. The thermal conductivity of the composite rod will be

asked Aug 21, 2018 by pady_1

1 answer

Figure shows a circuit that contains three identical resistors with resistance R = 9.0 $\Omega$ each, two identical inductors with inductance L = 2.0 mH each, and an ideal battery with emf $\varepsilon$ = 18 V. The current 'I' through the battery just after the switch closed is,â€¦â€¦..

asked Aug 21, 2018 by pady_1

1 answer

The bulk modulus of a sperical object is 'B'. If it is subjected to uniform pressure 'p', the fractional decrease in radius is :

asked Aug 21, 2018 by pady_1

1 answer

If $\theta_1$ and $\theta_2$ be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip $\theta$ is given by :

asked Aug 21, 2018 by pady_1

1 answer

Two blocks A and B of masses 3m and m respectively are connected by a massless and inextensible string. The whole system is suspended by a massless spring as shown in figure. The magnitudes of acceleration of A and B immediately after the string is cut, are respectively :

asked Aug 21, 2018 by pady_1

1 answer

A potentiometer is an accurate and versatile device to make electrical measurements of E.M.F. because the method involves :

asked Aug 21, 2018 by pady_1

0 answers

The two nearest harmonics of a tube closed at one end and open at other end are 220 Hz and 260 Hz. What is the fundamental frequency of the system ?

asked Aug 21, 2018 by pady_1

1 answer

The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is :

asked Aug 21, 2018 by pady_1

1 answer

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