JEE Main entrance exam Question Bank Solutions

A circular coil of 1000 turns each with area 1 m² is rotated about its vertical diameter at the rate of one revolution per second in a uniform horizontal magnetic field of 0.07T. The maximum voltage generation will be ______ V.

The maximum kinetic energy of the photoelectrons ejected will be ______ eV when the light of wavelength 350 nm is incident on a cesium surface. The work function of cesium = 1.9 eV.

Which of the following is used in optical fibres?

We wish to observe an object which is 2.5Å in size. The minimum energy photon that can be used ______.

A point isotropic light source of power P = 12 watts is located on the axis of a circular mirror of radius R = 3 cm. If the distance of the source from the centre of the mirror is a = 39 cm and the reflection coefficient of the mirror is α = 0.70 then the force exerted by the light ray on the mirror is ______ × 10^-10 N.

A charged dust particle of radius 5 × 10^-7 m is located in a horizontal electric field having an intensity of 6.28 × 10⁵ V/m. The surrounding medium is air with a coefficient of viscosity η = 1.6 × 10^-5 N-s/m². If the particle moves with a uniform horizontal speed of 0.02 m/s, the number of electrons on it is ______.

Two particles of equal mass 'm' go around a circle of radius R under the action of their mutual gravitational attraction. The speed of each particle with respect to its centre of mass is ______.

Find the gravitational force of attraction between the ring and sphere as shown in the diagram, where the plane of the ring is perpendicular to the line joining the centres. If `sqrt8` R is the distance between the centres of a ring (of mass 'm')and a sphere (mass 'M') where both have equal radius 'R'.

If 'S' is stress and 'Y' is young's modulus of the material of a wire, the energy stored in the wire per unit volume is ______.

A body of mass m = 10 kg is attached to one end of a wire of length 0.3 m. The maximum angular speed (in rad s^-1) with which it can be rotated about its other end in the space station is (Breaking stress of wire = 4.8 × 10⁷ Nm^-2 and the area of cross-section of the wire = 10^-2 cm²) is ______.

The area of the cross-section of the rope used to lift a load by a crane is 2.5 × 10^-4m². The maximum lifting capacity of the crane is 10 metric tons. To increase the lifting capacity of the crane to 25 metric tons, the required area of cross-section of the rope should be ______.

(take g = 10 ms^-2)

Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will ______.

At room temperature, a diatomic gas is found to have an r.m.s. speed of 1930 ms^-1. The gas is ______.

Which of the following expressions corresponds to simple harmonic motion along a straight line, where x is the displacement and a, b, and c are positive constants?

Assume there are two identical simple pendulum clocks. Clock - 1 is placed on the earth and Clock - 2 is placed on a space station located at a height h above the earth's surface. Clock - 1 and Clock - 2 operate at time periods 4 s and 6 s respectively. Then the value of h is ______.

(consider the radius of earth R_E = 6400 km and g on earth 10 m/s²)

n mole of a perfect gas undergoes a cyclic process ABCA (see figure) consisting of the following processes:

A `→` B: Isothermal expansion at temperature T so that the volume is doubled from V₁ to V₂ = 2V₁ and pressure changes from P₁ to P₂.

B `→` C: Isobaric compression at pressure P₂ to initial volume V₁.

C `→` A: Isochoric change leading to change of pressure from P₂ to P₁.

Total workdone in the complete cycle ABCA is ______.

A 25 m long antenna is mounted on an antenna tower. The height of the antenna tower is 75 m. The wavelength (in meter) of the signal transmitted by this antenna would be ______.

In thermodynamics, heat and work are ______.

A carrier wave V_c(t) = 160 sin(2π × 10⁶t) volts is made to vary between V_max = 200 V and V_min = 120 V by a message signal V_m(t) = A_m sin(2π × 10³t) volts. The peak voltage Am of the modulating signal is ______.

• Statement I: By doping silicon semiconductor with pentavalent material, the electrons density increases.
• Statement II: The n-type semiconductor has net negative charge. In the light of the above statements, choose the most appropriate answer from the options given below: