List of practice Questions

Earth’s magnetic field always has a horizontal component except at
A tightly wound long solenoid has ‘n’ turns per unit length, a radius ‘r’ and carries a current I. A particle having charge ‘q’ and mass ‘m’ is projected from a point on the axis in a direction perpendicular to the axis. The maximum speed of the particle for which the particle does not strike the solenoid is
A toroid with thick windings of N turns has inner and outer radii R1 and R2 respectively. If it carries certain steady current I, the variation of the magnetic field due to the toroid with radial distance is correctly graphed in
In Bryophytes & Pteridophytes the number of male gametes produced is several thousand times the numbe of female gametes produced.
Reason : Large number of male gametes fail to reach the female gametes during transport.
How many microsporangia are located at the corners of a typical bilobed anther of angiosperm ?
Two parallel wires in free space are 10 cm apart and each carries a current of 10A in the same direction. The force exerted by one wire on the other [per unit length] is
A strong magnetic field is applied on a stationary electron. Then the electron
Consider an electrical conductor connected across a potential difference V. Let Δq be a small charge moving through it in time Δt. If I is the electric current through it,
(I) the kinetic energy of the charge increases by IVΔt.
(II) the electric potential energy of the charge decreases by IVΔt.
(III) the thermal energy of the conductor increases by IVΔt.
Then the correct statement/s is / are
A copper wire of length 1 m and uniform cross sectional area 5 × 10-7 m2 carries a current of 1 A. Assuming that there are 8 × 1028 free electrons per m3 in copper, how long will an electron take to drift from one end of the wire to the other?
In the given arrangement of experiment on metre bridge, if AD corresponding to null deflection of the galvanometer is X, what would be its value if the radius of the wire AB is doubled?
experiment on metre bridge
A wire of resistance 3Ω is stretched to twice its original length. The resistance of the new wire will be
In figure, charge on the capacitor is plotted against potential difference across the capacitor. The capacitance and energy stored in the capacitor are respectively.
Graph of charge on the capacitor
An electrician requires a capacitance of 6 μF in a circuit across a potential difference of 1.5 kV. A large number of 2 μF capacitors which can withstand a potential difference of not more than 500 V are available. The minimum number of capacitors required for the purpose is
Which of the statements is false in the case of polar molecules?
Eight drops of mercury of equal radii combine to form a big drop. The capacitance of a bigger drop as compared to each smaller drop is
If a slab of insulating material (conceptual) 4 × 10-3 m thick is introduced between the plates of a parallel plate capacitor, the separation between the plates has to be increased by 3.5 × 10-3m to restore the capacity to original value. The dielectric constant of the material will be
A 2 – gram object, located in a region of uniform electric field \(\vec{E}=(300\ N\ C^{-1})\hat{i}\) carries a charge Q. The object released from rest at x = 0 , has a kinetic energy of 0.12 J at x = 0.5 m. Then Q is
Electric field due to infinite, straight uniformly charged wire varies with distance ‘r’ as
A copper rod AB of length l is rotated about end A with a constant angular velocity ω. The electric field at a distance x from the axis of rotation is
To propagate both longitudinal and transverse waves, a material must have
A number of Carnot engines are operated at identical cold reservoir temperatures (TL). However, their hot reservoir temperatures are kept different. A graph of the efficiency of the engines versus hot reservoir temperature (TH) is plotted. The correct graphical representation is
A gas mixture contains monoatomic and diatomic molecules of 2 moles each. The mixture has a total internal energy of (symbols have usual meanings)
Two capillary tubes P and Q are dipped vertically in water. The height of water level in capillary tube P is \(\frac{2}{3}^{rd}\) of the height in capillary tube Q. The ratio of their diameter is _______.
Which of the following curves represent the variation of coefficient of volume expansion of an ideal gas at constant pressure?
Two bodies of masses 8 kg are placed at the vertices A and B of an equilateral triangle ABC. A third body of mas 2 kg is placed at the centroid G of the triangle. If AG = BG = CG = 1 m, where should a fourth body of mass 4 kg be placed so that the resultant force on the 2 kg body is zero?