List of practice Questions

A particle is moving with constant speed in a circular path. When the particle turns by an angle \(90\degree\) , the ratio of instantaneous velocity to its average velocity is \(π : x\sqrt2\). The value of x will be -

The mean free path of molecules of a certain gas at STP is 1500d, where d is the diameter of the gas molecules. While maintaining the standard pressure, the mean free path of the molecules at 373K is approximately

For designing a voltmeter of range 50 V and an ammeter of range 10 mA using a galvanometer which has a coil of resistance 54Ω showing a full scale deflection for 1 mA as in figure.

(A) for voltmeter R ≈ 50 kΩ  
(B) for ammeter r ≈ 0.2Ω  
(C) for ammeter r ≈ 6Ω  
(D) for voltmeter R ≈ 5 kΩ (E) for voltmeter R ≈ 500Ω 
Choose the correct answer from the options given below :
 

A 12.5 eV electron beam is used to bombard gaseous hydrogen at room temperature. The number of spectral lines emitted will be

A particle is executing Simple Harmonic Motion (SHM). The ratio of potential energy and kinetic energy of the particle when its displacement is half of its amplitude will be

The current sensitivity of moving coil galvanometer is increased by 25%.This increase is achieved only by changing in the number of turns of coils and area of cross section of the wire while keeping the resistance of galvanometer coil constant. The percentage change in the voltage sensitivity will be :

Which of the following statements are correct?
A. Electric field lines are always perpendicular to equipotential lines.
B. A zero electric field inside a conducting sphere does not mean that the potential gradient is also zero
C. The resultant of two electric fields is determined by vector addition of the two field strengths
D. If the field lines get closer together at any place, it means that the field strength is decreasing
E. The resultant potential at a point is just the sum of the individual potentials.
Choose the correct answer from the options given below:

A bar magnet when suspended horizontally and perpendicular to earth's field experiences a torque of 3 x 10^-4 Nm. The Magnetic moment of the magnet would be:
(take horizontal component of Earth's magnetic field at the place 0.4 × 10^-4T)

What is the magnetic force acting on a proton (charge +1.6 × 10^-19C) moving at an angle of 30° across a magnetic field of 5.3 x 10³ T at a speed of 3.0 x 10⁵ ms^-1?

The forbidden energy band gap in conductors, semi conductors and insulators are E_G1, E_G2 and E_G3, respectively. The relation among them is

Match List I with List II

Choose the correct answer from the options given below:

Two sitar stings A and B playing a note are slightly out of tune and produces beats of frequency 5 Hz. The tension in string B is slightly increased and beat frequency become 3 Hz. What is the original frequency of B if frequency of A is 427 Hz.

Match List I with List II

Choose the correct answer from the options given below:

Two charges 5 µC and -2 µC (with no external field) are placed at (-9 cm, 0, 0) and (9 cm, 0, 0) respectively. The work required to separate the two charges infinitely away from each other is :

Which of the following statement is correct for a potentiometer ?

At a place, the horizontal component of earth's magnetic field is $4 \times 10^{-4}T$ and angle of dip is 60°. The value of horizontal component of earth's magnetic field at the equator is :

Match List I with List II

	LIST I		LIST II
A.	Magnetic dipole moment	I.	Weber/$m^2$
B.	Magnetic permeability	II.	Am (Ampere m)
C.	Pole strength	III.	Henry/m
D.	Magnetic flux density	IV.	$Am^2$ (Ampere $m^2$)

Choose the correct answer from the options given below:

A charge of 5 μC moves with a speed of $2 \times 10^6$ m/s along the positive y-axis. A magnetic field $\vec{B}$ of strength ($2\hat{i}+ \hat{k}$)T exists in space. The magnetic force acting on the charge is :

The circuits where transformers are used:

Following are the wavelength of some constituents of the electromagnetic spectrum. The wavelength range that are used in Radar system for Aircraft navigation is:
(A) 1 mm to 700 nm
(B) 0.1 m to 1 mm
(C) 400 nm to 1 nm
(D) < 10-3 nm
(E) > 1m
Choose the correct answer from the options given below:

The logic gate realised using p-n junction diodes in the given figure is:

For a medium with permittivity (e) and permeability (µ), the speed of light (v) is given by:

Choose the correct alternative from the following:

An isolated sphere has a capacitance of 60 pF, what is the radius of the sphere?