BITSAT Practice Test - 14 - JEE MCQ

A piece of Aluminium and Germanium each are cooled from T₁ k to T₂ k. The resistance of

Three resistors are connected to form the sides of a triangle ABC, the resistance of the sides AB, BC and CA are 40 ohms, 60 ohms and 100 ohms respectively. The effective resistance between the points A and B in ohms will be

Which of the following statements is correct

Threshold wavelength for photoelectric emission from a metal surface is 5200 Å. Photoelectrons will be emitted when this surface is illuminated with monochromatic radiation from

The number of turs of primary and secondary coils of a transformer are 5 and 10 respectively and mutual inductance of the transformer is 25 H. Now, number of turns in primary and secondary are made 10 and 5 respectuvely. Mutual inductance of transformer will be

The capacitor of a parallel plate capacitor with no dielectric substance and a separation of 0.4 cm is 2 μF. The separation is reduced to half and it is filled with a substance of dielectric value 2.8. The new capacity of the capacitor is

Two concentric uniformly charged spheres of radius 5cm and 10cm are arranged as shown in the figure. Potential difference between the spheres is:

A block of mass 10 kg is placed on an inclined plane. When the angle of inclination is 30 o, the block just begins to side down the plane. The force of static friction is

The angular velocity of rotation of star at which the matter strat to escape from its equator will be

A perfect black body emits radiation at temperature 300 K. If it radiates 16 times this amount, then its temperature will be

One litre of Helium gas at a pressure 76 cm of Hg and temperture 27^o is heated till its pressure and volume are doubled. The final temperature attained by the gas is

If current in a moving coil galvanometer is increased by 1%, then percentage increase in its deflection will be

A bar magnet is held perpendicular to a uniform magnetic field. If the couple acting on the magnet is to be halved by rotating it, then the angle by which it is to be rotated is

What should be the minimum average velocity of water in a small tube of radius 5 mm, so that the flow is just turbulent? (Given: Viscosity of water=0.01 poise and density of water = 1000 kg-m⁻³)

The neck and bottom of a bottle are 3 cm and 15 cm in radius respectively. If the cork is pressed with a force 12 N in the neck of the bottle, then force exerted on the bottom of the bottle is

Two similar wires under the same load yield elongations of 0.1 mm and 0.05 mm respectively. If the area of cross-section of the first wire is 4 mm², then the area of cross-section of the second wire is

A stone is released from the top of a tower. If its velocity at half of the height is 10 m−s−¹, then height of the tower is (Take g = 10 m−s⁻²)

For a particle in a uniformly accelerated circular motion

The resultant of two forces acting at an angle of 150^o is 10 N and is perpendicular to one of the forces. The other force is

A body weighs 8 gm when placed in one pan and 18 gm when placed on the other pan of a false balance. If the beam is horizontal when both the pans are empty, the true weight of the body is

The length of a telescope is 36 cm. The focal lengths of its lenses can be

A mass M is suspended from the spring of negligible mass. The spring is pulled a little and then released, so that the mass executes simple harmonic motion of time period T. If the mass is increased by m, the time period becomes 5T/3. The ratio m/M is

A body esecutes S.H.M. with amplitude A₀. At what displacement from the mean position, potential energy is one-fourth of its total energy?

A compound microscope has two lenses. The magnifying power of one is 5 and the combined magnifying power is 100. The magnifying power of the other lens is

A cylindrical solid of mass M has radius R and length L. Its moment of inertia about a generator is

Which of the following statements are correct when a gymnast sitting on a rotating stool with his arms outstretched, suddenly lowers his hands?

1. The angular velocity decreases.
2. The angular velocity increases.
3. The moment of inertia decreases.
4. The moment of inertia increases.
Select the answers using the codes given below.

Two identical particles move towards eachother with velocity 2ν and ν respectively. The velocity of centre of mass is