WBJEE Physics Test - 2 - JEE MCQ

On increasing the temperature of a conductor, its resistance increases because

A thin spherical conducting shell of radius R has charge q. Another charge Q is placed at the centre of the shell. The electrostatic potential at a point P at a distance R/2 from the centre of the shell is

The length of an elastic string is 'a' meters when the longitudinal tension is 4N and 'b' meters when the longitudinal tension is 5N. The length of the string in meters when the longitudinal tension is 9N is

The force of gravity is least at

When two surfaces are coated with a lubricant, then they

The capacity of a condenser with two identical plates separated by a distance 'd' in air is 'C'. If the distance of separation is reduced to d 2 , the capacity is

A potential difference of 2V exists across a potentiometer wire of 2m length. When the potential difference across a 2Ω resistance of a second circuit is measured by this potentiometer wire, it amounts to 5mm balancing length. The current in the second circuit is

An electron revolves in a circle of radius 0.4 Å with a speed of 10⁶ms⁻¹ in a hydrogen atom. The magnetic field produced at the centre of the orbit due to the motion of the electron in tesla is [μ₀ = 4π x 10⁻⁷Hm⁻¹ ; change on the electron = 1.6 x 10⁻¹⁹C]

If a diamagnetic solution is poured into a U-tube and one arm of this U-tube is placed between the poles of a strong magnet, with the meniscus in line with the field, then the level of solution will

Sixty four spherical rain drops of equal size are falling vertically through air with a terminal velocity 1.5 m-s^⁻1. If these drops coalesce to form a big spherical drop, then terminal velocity of big drop is

A body of mass 0.4 kg is whirled in a vertical circle making 2 rev/sec. If the radius of the circle is 2 m, then tension in the string when the body is at the top of the circle, is

Which of the following is a vector quantity?

A radioactive element has a half life of 15 years. The fraction that will decay in 30 years is

Two masses m₁ and m₂ are suspended together by a massless spring of spring cosntant k. When the masses are in equilibrium, m₁ is removed without disturbing the system, then the angular velocity of oscillation of m₂ is

A body A going from south to North and body B is going from west to east. Then direction of relative velocity of A with respect to B is

Which one of the following statements is true for the speed (ν) and the acceleration (α) of a particle simple harmonic motion?

A convex lens of focal length 0.5 m and concave lens of focal length 1 m are combined .The power of resulting lens will be

From a uniform wire, two circular loops are made i) P of radius 'r' and ii)Q of radius nr. If the moment of inertia of Q about an axis passing through its centre and perpendicular to its plane is 8 times that of P about a similar axis, the value of 'n' is (diameter of the wire is very much smaller than r or nr)

If rotational kinetic energies of two bodies having moments of inertia of 9 kg-m² and 1 kg-m² are same, then ratio of their angular momenta is

The depletion of layer in the p-n junction region is caused by

Heat given to a body which rises its temperature by 1ºC is

The potential barrier, in the depletion of layer, is due to

A process in which volume remains constant is called

A unit vector perpendicular to each of the vectors (-6î+8k̂), (8î+6k̂) forming a right handed system is

Soap bubble looks coloured due to

The unit of electric flux is

A car moving with a speed of 40 km/h can be stopped by applying brakes after atleast 2m. If the same car is moving with a speed of 80 km/h, what is the minimum stopping distance ?