Physics Mock Test-7

The heat dissipated in a resistance can be obtained by measuring of resistance, the current and time. The maximum error in the measurement of these quantities is 1%, 2% and 1% respectively. The maximum error in the direction of the dissipated heat is

The dimensional formula for Young’s modulus is

A generator at a utility company produces 100 A of current at 4000 V. The voltage is stepped up to 240000 V by a transformer before it is sent on a high voltage transmission line. The current in transmission line is

A choke is preferred to a resistance for limiting current in AC circuit because

A heavy nucleus at rest breaks into two fragments which fly off with velocities in the ratio 8:1. The ratio of radii of the fragments is

The mass number of nucleus is always

A battery having e.m.f. 4 volt and internal resistance 0.5 Ω is connected with a resistance of 4.5 Ω, then the voltage at the terminal of battery is

A galvanometer acting as a voltmeter will have

Calcium plate has a maximum possible radiation wavelength 400 nm to eject electrons. Its work function is

A particle of mass 1 mg has the same wavelength as an electron moving with a velocity of 3 x 10⁶ ms⁻¹. The velocity of the particle is

If the minimum energy of photons needed to produce photoelectrons is 3 eV, bombardinbg the photoelectric material by a number of photons of 2.5 eV also one can get

A coil of resistance and 1.0 H inductance is connected to an a.c. source of frequency 200/2π Hz. Phase angle between potential and current will be

A metal conductor of length 1m rotates vertically about one of its ends at angular velocity 5 radian per second. If the horizontal component of earth’s magnetic field is 0.2×10⁻⁴ T, then the e.m.f. developed between the two ends of the conductor is

An LED is constructed from a p-n junction based on a certain semi-conducting material whose energy gap is 1.9 eV. Then, the wavelength of the emitted light is

In N-type semi-conductor current is due to

A Gaussian surface in the cylinder of cross-section πa² and length L is immersed in a uniform electric field E with the cylinder axis parallel to the field.The flux ? of the electric field through the closed surface is

A capacitor of capacitance 100μF is charged by connecting it to a battery of voltage 12V with internal resistance 2Ω. The time after which 99% of the maximum charge is stored on the capacitor is

In some region, gravitational field is zero. The gravitational potential in this region

Suppose for some reasons, radius of earth were to shrink by 1% of present value, mass remaining same, then g(acceleration due to gravity), will change by

A roller coaster is designed such that riders experience “weightlessness” as they go round the top of a hill whose radius of curvature is 20 m. The speed of the car at the top of the hill is between

A pellet of mass 1 g is moving with an angular velocity of 1 rad/s along a circle of radius 1 m the centrifugal force is

A bar magnet of moment M and pole strength m is cut into parts of equal lengths. The magnetic moment and pole strength of either part is

A circuit area 0.01 m² is kept inside a magnetic field which is normal to its plane. The magnetic field changes from 2 tesla to 1 tesla in 1 milli second. If the resistance of the circuit is 2 Ω. The amount of heat evolved is

A super conductor exhibits perfect

The equations of motion of a projectile are given by x=36 t metre and 2y=96t-9.8t² metre. The angle of projection is

The circular motion of a particle with constant speed is

A particle moving along x-axis has acceleration f, at time t, given by f=f₀(1-t/T), where f₀ and T constants. The particle at t=0 has zero velocity. In the time travel between t=0 and the instant when f=0, the particle’s velocity (vx) is

A bullet emerges from a barrel of length 1.2 m with a speed of 640 ms⁻¹. Assuming constant acceleration, the approximate time that it spends in the barrel after the gun is fired is

Angular momentum of the particle rotating with a central force is constant due to

A thin rod of length L and mass M is held vertically with one end on the floor and is allowed to fall. Find the velocity of other end when it hits the floor, assuming that the end on the floor does not slip

The point of suspension λ of a simple pendulum with normal time period T₁ is moving upward according to equation y=kt² where k=1 m/s². If new time period is T² the ratio T₁²/T₂² will be

The amplitude of S.H.M. y=2 (sin 5πt+√2 cos 5πt) is

If the temperature of the sun were to increase from T to 2T and its radius from R and 2R, then the ratio of the radiant energy received on earth to what it was previously will be

A wire is suspended vertically from one of its ends is stretched by attaching a weight of 200 N to the lower end. The weight stretches the wire by 1 mm. Then the elastic energy stored in the wire is

The approxiamate ratio of nuclear mass densities of ₇₉Au¹⁹⁷ and ₄₇ Ag¹⁰⁷ nuclei is

A magnifying glass of focal length 5 cm is used to view an object by a person whose smallest distance of distinct vision is 25 cm. If he holds the glass close to eye, then the magnification is

The speed of light in media M₁ and M₂ are 1.5×10⁸ ms⁻¹ and 2×10⁸ ms⁻¹ respectively. A ray travels from medium M₁ to the medium M₂ with an angle of incidence θ. The ray suffers total internal reflection. Then, the value of the angle of incidence θ is

Initial pressure and volume of a gas are P and 800cc. If the final volume is 100cc and γ=5/3, then the final pressure equals to

For a diatomic gas charge in internal energy for unit charge in temperature for constant pressure and constant volume is U₁ and U₂ respectively. U₁ : U₂ is

In Young’s double slit experiment, when wavelength used is 6000Å and the screen is 40 cm from the slits, the fringes are 0.012 cm wide. What is the distance between the slits?

If two slits in Young’s experiment are 0.4 mm apart and fringe width on a screen 200 cm away is 2 mm, the wavelength of light illuminating the slits is

If the length of a stretched string is shortened by 4% and the tension is increased by 44%, then the ratio of the final and initial fundamental frequencies is

Find the fundamental frequency of a closed pipe if the length of air column is 42m. (Speed of sound in air=332 m/sec)

A block of mass 0.50 kg is moving with a speed of 2.00 ms⁻¹ on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Two bodies A and B have masses 20 Kg and 5 Kg respectively. Each one is acted upon by a force of 4 kg wt. If they acquire the same kinetic energy in times tᴀ and tʙ, then the ratio tᴀ/tʙ