Physics Mock Test-9

Dimensional formula of magnetic field in terms of mass M, length L, time T and Charge Q is

Dimensions of resistance in an electrical circuit, in terms of dimension of mass M, of length L, of time T and of current I would be

A series combination of resistor (R), capacitor (C), is connected to an AC source of angular frequency ω. Keeping the voltage same, if the frequency is changed to ω/3, the current becomes half of the original current. Then the ratio of the capacitive reactance and resistance at the former frequency is

A nucleus at rest splits into two nuclear parts having radii in the ratio 1:2. Their velocities are in the ratio

If an electron and a positron annihilate, the energy released is

A battery of emf 10 V and internal resistance 3 ohm is connected to a resistor. The current in the circuit is 0.5 A. The terminal voltage of the battery when the circuit is closed is

A galvanometer having resistance of 50 Ω requires a current of 100μA to give full scale deflection. How much resistance is required to convert it into an ammeter of range of 10A?

Characteristic X-rays are produced due to

A photocell employs photoelectric effect to convert

Which one of the following statements is WRONG in the context of X-rays generated from a X-ray tube?

A straight conductor of length 0.4 m is moved with a speed of 7 ms⁻¹perpendicular to a magnetic field of intensity 0.9 Wbm⁻². The induced emf across the conductor is

In a coil having e.m.f. of 8 V induced for 0.05 s. The value of current changes from 2 A to 4 A. The value of coefficient of self induction of the coil is

A leaf which contains only green pigments is illuminated by a laser light of wavelength 0.6328 μm. It would appear to

Avalanche breakdown is due to

A pure semiconductor behaves slightly as a conductor at

A hollow sphere of charge does not produce an electric field at any

A charge of 100 μC has a potential at a distance of 9 m is

Periodic time of a satellite revolving above Earth’s surface at a height equal to R, radius of Earth is (g=acceleration due to gravity at Earth’s surface)

An artificial satellite is revolving round the earth in a circular orbit. Its velocity is half the escape velocity. Its height from earth’s surface is

A body of mass 4 kg is accelerated upon by a constant force travels a distance of 5 m in the first second and a distance of 2 m in the third second. The force acting on the body is

Force required to move a mass of 1kg at rest on a horizontal rough plane (μ = 0.1 and g = 9.8 m/s²) is

A bar magnet of pole strength 10 A-m is cut into two equal parts breadthwise. The pole strength of each magnet is

A moving coil galvanometer of resistance 100 Ω is converted to ammeter by a resistance of 0.1 Ω in the circuit. Galvanometer gives full scale deflection at 100 μA. The minimum current in the circuit for maximum deflection is

For a given velocity, a projectile has the same range R for two angles of projection. If t₁ and t₂ are the times of flight in the two cases, then

The angle between the vectors (i+j) and (j+k) is

An aeroplane is flying horizontally with a velocity of 216 km/h at a height of 1960 m. When it is vertically above a point A on the ground, a bomb is released from it. The bomb strikes the ground at point B. The distance AB is(ignoring air resistance)

The distance travelled by a particle starting from rest and moving with an acceleration 4/3 ms⁻², in the third second is

The ratio of the radii of gyration of a circular disc to that of a circular ring, each of same mass and radius, around their respective axes is

Four point masses, each of value m, are placed at the corners of a square ABCD of side l. The moment of inertia of this system about an axis through A and parallel to BD is

The length of second pendulum is 1 m on earth. If mass and diameter of the planet is double than that of earth, then length becomes

A simple pendulum is suspended from the ceiling of a lift. When the lift is at rest its time period is T. With what acceleration should the lift be accelerated upwards in order to reduce its period to T/2? (g is the acceleration due to gravity)

Four identical rods are joined to from a square. If the temperature difference across one diagonal is 100° C, then temperature difference across another diagonal will be

If the rise in height of capillary of two tubes is 6.6 cm and 2.2 cm, then the ratio of the radius is

Activity of a radioactive sample decreases to (1/3)rd of its original value in 3 days. Then, in 9 days its activity will become

If doubly ionised lithium atom is hydrogen like with atomic number 3, the wavelength of radiation required to excite the electron in Li⁺⁺ from the first to the third Bohr orbit and the number of different spectral lines observed in the emission spectrum of the above excited system are

An air bubble in a glass slab with refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness ( in cm) of the slap is

A thin glass(refractive index 1.5) lens has optical power of -5D in air. Its optical power in a liquid medium with refractive index 1.6 will be

The molar specific heat at constant pressure of an ideal gas is (7/2)R. The ratio of specific heat at constant pressure to that at constant volume is

An ideal heat engine works between temperature T₁=500 K and T₂=375 K. If the engine absorbs 600J of heat from the source then the amount of heat released to the sink is

Two coherent monochromatic beams of intensities I and 4I respectively, are superposed. Then, the maximum and minimum intensities in the resulting pattern are

Which of the following phenomena support the wave theory of light?
1. Scattering
2. Interference
3. Diffraction
4. Velocity of light in a denser medium is less than the velocity of light in the rare medium

If fundamental frequency of closed pipe is 50 Hz then frequency of 2nd overtone is

A point source emits sound equally in all directions in a non-absorbing medium. Two points P and Q are at distances of 2 m and 3 m respectively from the source. The ratio of the intensities of the waves at P and Q is

The potential energy of a 1 kg particle free to move along the x-axis is given by
V(x)={x⁴/4-x²/2}J.
The total mechanical energy of the particle 2 J. Then, the maximum speed (in m/s) is

A cricket ball of mass 250 g collides with a bat with velocity 10 m/s and returns with same velocity within 0.01 seconds. The force acted on bat is