Physics Mock Test-8

Which of the following pairs is wrong

The difference in the lengths of a mean solar day and a sidereal day is about

A L-C-R circuit with L=1.00 mH, C=10μF and R=50Ω, is driven with 5 V AC voltage. At resonance, the current through the circuit is

A nuclear reaction is given as 4 ₁H¹→₂He⁴+₀e¹+energy Mention the type of reaction.

Ratio of longest wavelengths corresponding to Lyman and Balmer series in hydrogen spectrum is

A galvanometer having internal resistance 10Ω requires 0.01 A for a full scale deflection. To convert this galvanometer to a voltmeter of full scale deflection at 120V, we need to connect a resistance of

A battery of e.m.f. E and internal resistance r is connected to an external resistance R the condition for maximum power transfer is

Cathode rays are produced when the pressure is of the order of

When photons of energy hν fall on an aluminium plate (of work function E₀), photoelectrons of maximum kinetic energy K are ejected. If the frequency of radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be

Light is emitted when

A rectangular copper coil is placed in a uniform magnetic field of induction 40 mT with its plane perpendicular to the field. The area of the coil is shrinking at a constant rate of 0.5 m²s⁻¹.The emf induced in the coil is

A straight conductor 0.1 m long moves in a uniform magnetic field 0.1 T. The velocity of the conductor is 15 ms⁻¹ and is directed perpendicular to the field. The emf indued between the two ends of the conductor is

Application of a forward bias to a P-N junction

A p-n-p transistor is used in common emitter mode in an amplifier circuit. When base current is changed by an amount ∆Iв, then the collector current changes by 4 mA. If the current amplification factor is 60, then the value of ∆Iв is,

A hollow metal sphere of radius 10 cm is charged such that the potential on its surface is 80V. The potential at the centre of the sphere is

A capacitor of capacitance value 1 μF is charged to 30 V and the battery is then disconnected. If it is connected across a 2 μF capacitor, the energy lost by the system is

A siren emitting sound of frequency 800 Hz is going away from a static listener with a speed of 30 m/s. The frequency of sound heard by listener is (velocity of sound = 300 m/s)

Infinite number of masses, each 1 kg, are placed along the x-axis at x= ±1 m, ±2 m, ±4 m, ±8 m, ±16 m ……. The magnitude of the resultant gravitational potential in terms of gravitational constant G at the origin (x=0) is

A block of wood weighs 10 N and is resting on an inclined plane. The coefficient of friction is 0.7. The frictional force that acts on the block, when the plane is 30° inclined with the horizontal is

A rocket is ejecting 50 g of gases per sec at a speed of 500 m/s. The accelerating force on the rocket will be

A bar magnet of moment of inertia I is vibrated in a magnetic field of induction 0.4×10⁻⁴ T. The time period of vibration is 12 s. The magnetic moment of the magnet is 120Am². The moment of inertia of the magnet is (in kgm²) approximately

A circular coil of radius 10cm and 100 turns carries a current 1 A. What is the magnetic moment of the coil?

Which of the following particles will have minimum frequency of revolution when projected with the same velocity perpendicular to a magnetic field?

In a uniform circular motion,

A proton of mass 1.6×10⁻²⁷ kg goes round in a circular orbit of radius 0.10 m under a centripetal force of 4×10⁻¹³ N. The frequency of revolution of the proton is about

The distance travelled by an object along a straight line in time t is given by s=3-4t+5t², the initial velocity of the object is

3 persons are initially at the 3 corners of an equilateral triangle whose side is equal to d. Each person now moves with a uniform speed v in such a way that the first moves directly towards the second and second directly towards the 3rd and 3rd directly towards the first. 3 persons will meet after a time equal to

Mass and diameter of a ring is 2 kg and 1 m respectively. The moment of inertia of ring about an axis is passing through its C.M. and perpendicular to the plane of the ring is

A ball rolls without slipping. The raidus of gyration of the ball about an axis passing through its centre of mass is K. If the raidus of ball be R, then the fraction of total energy associated with its rotational energy will be

When a mass m is attached to a spring, it normally extends by 0.2 m. The mass m is given a slight extension and released. Its time period will then be

The maximum velocity of a particle, executing simple harmonic motion with an amplitude 7 mm, is 4.4 m/s. The period of oscillation is

A black body at a temperature of 227⁰C radiates heat at a rate of 20 cal m⁻²s⁻¹. When its temperature is raised to 727⁰C, the heat radiated by it in cal m⁻²s⁻¹ will be closest to

If the terminal speed of a sphere of gold (density=19.5 kg/m³) is 0.2 m/s in a viscous liquid (density=1.5 kg/m³) find the terminal speed of a sphere of silver (density 10.5 kg/m³) of the same size in the liquid

The half-life of radioactive element is 600 yr. The fraction of sample that would remain after 3000 yr is

An α-particle of energy 5 MeV is scattered through 180⁰ by a fixed uranium nucleus. The distance of the closest approach is of the order of

The mirrors are inclined at an angle of 50⁰. The number of images formed for an object placed in between the mirrors is

Two thin lenses when placed in contact, then the power of combination is +10 D. If they are kept 0.25 m apart, then the power reduces to +6 D. The focal lengths of the lenses (in m) will be

A Carnot engine takes heat from a reservoir at 627⁰C and rejects heat to a sink at 27⁰C. Its efficiency will be

Efficiency of a Carnot engine is 50% when temperature of sink is 500K. In order to increase efficiency up to 60% keeping temperature of source remains the same, temperature of sink is

A beam of light of wavelength 590 nm is focussed by a converging lens of diameter 10 cm at a distance of 20 cm form it. Find the diameter of the disc image formed

A fringe width of a certain interference pattern is β=0.002 cm. What is the distance of 5th dark fringe centre?

Velocities of sound measured in hydrogen and oxygen gas at a given temperature will be in the ratio

An open pipe resonates with a tuning fork of frequency 500 Hz. It is observed that two successive nodes are formed at distances 16 cm and 46 cm from the open end. The speed of sound in air in the pipe is

A particle of mass 100 g is thrown vertically upwards with a speed of 5 m/s. The work done by the force of gravity during the time the particle goes up is

The height of the dam, in an hydroelectric power station is 10 m. In order to generate 1 MW of electric power, the mass of water (in Kg) that must fall per second on the blades on the turbine is