List of top Physics Questions

A charge particle moves along circular path in a uniform magnetic field in a cyclotron. The kinetic energy of the charge particle increases to 4 times its initial value. What will be the ratio of new radius to the original radius of circular path of the charge particle
Amplitude modulated wave is represented by VAM = 10[1+0.4cos(2π×104t] cos(2π×107t). The total bandwidth of the amplitude modulated wave is:
Following statements related to radioactivity are given below:
(A) Radioactivity is a random and spontaneous process and is dependent on physical and chemical conditions.
(B) The number of un-decayed nuclei in the radioactive sample decays exponentially with time.
(C) Slope of the graph of loge (no. of undecayed nuclei) Vs. time represents the reciprocal of mean life time (τ).
(D) Product of decay constant (λ) and half-life time (T1/2) is not constant.
Choose the most appropriate answer from the options given below:

Given below are two statements : one is labelled as AssertionA and the other is labelled as ReasonR.

Assertion A : The photoelectric effect does not takes place, if the energy of the incident radiation is less than the work function of a metal.

Reason R :Kinetic energy of the photoelectrons is zero, if the energy of the incident radiation is equal to the work function of a metal.

In the light of the above statements, choose the most appropriate answer from the options given below.

Three identical particles A, B and C of mass 100 kg each are placed in a straight line with AB = BC = 13 m. The gravitational force on a fourth particle P of the same mass is F, when placed at a distance 13 m from the particle B on the perpendicular bisector of the line AC. The value of F will be approximately
An ice cube of dimensions 60 cm × 50 cm × 20 cm is placed in an insulation box of wall thickness 1 cm. The box keeping the ice cube at 0°C of temperature is brought to a room of temperature 40°C. The rate of melting of ice is approximately. (Latent heat of fusion of ice is \(3.4 × 10^5\) \(J kg^{–1 }\)and thermal conducting of insulation wall is \(0.05\) \(Wm^{–1}\)°\(C^{–1})\)

A bullet is shot vertically downwards with an initial velocity of 100 m/s from a certain height. Within 10s, the bullet reaches the ground and instantaneously comes to rest due to the perfectly inelastic collision. The velocity-time curve for total time t = – 20s will be 

(Take g = 10 m/s2)

BX and BY are the magnetic field at the centre of two coils X and Y, respectively each carrying equal current. If coil X has 200 turns and 20 cm radius and coil Y has 400 turns and 20 cm radius, the ratio of BX and BY is
7 mol of a certain monoatomic ideal gas undergoes a temperature increase of 40 K at constant pressure. The increase in the internal energy of the gas in this process is:
(Given R = 8.3 JK–1 mol–1)
A transverse wave is represented by \(y = 2sin(ωt – kx)\) \(cm\). The value of wavelength (in cm) for which the wave velocity becomes equal to the maximum particle velocity, will be
In a series \(LR\) circuit \(X_L=R\) and power factor of the circuit is \(P_1\). When capacitor with capacitance C such that \(X_L=X_C\) is put in series, the power factor becomes \(P_2\). The ratio \(\frac {P_1}{P_2}\) is
A radio can tune to any station in 6 MHz to 10 MHz band. The value of corresponding wavelength bandwidth will be
A nucleus of mass M at rest splits into two parts having masses \(\frac{M′}{3}\) and \(\frac{2M′}{3}(M′<M).\)
The disintegration rate of a certain radioactive sample at any instant is 4250 disintegrations per minute. 10 minutes later, the rate becomes 2250 disintegrations per minute. The approximate decay constant is
(Take log101.88 = 0.274)

Choose the correct answer.

1. A torque meter is calibrated to reference standards of mass, length and time each with 5% accuracy. After calibration, the measured torque with this torque meter will have net accuracy of

A body is projected vertically upwards from the surface of earth with a velocity equal to one third of escape velocity. The maximum height attained by the body will be:
The total charge on the system of capacitors C1 = 1 μF, C2 = 2 μF, C3 = 4 μF and C4 = 3 μF, connected in parallel is :
(Assume a battery of 20 V is connected to the combination)
When a particle executes Simple Harmonic Motion, the nature of graph of velocity as a function of displacement will be :
Light travels in two media \(M_1\) and \(M_2\) with speeds \(1.5 × 10^8ms^{–1 }\)and \(2.0 × 10^8ms^{–1}\), respectively. The critical angle between them is:
The current I in the given circuit will be
The current I in the given circuit
A gas has n degrees of freedom. The ratio of specific heat of gas at constant volume to the specific heat of gas at constant pressure will be

A bag is gently dropped on a conveyor belt moving at a speed of 2 m/s. The coefficient of friction between the conveyor belt and bag is 0.4. Initially the bag slips on the belt before it stops due to friction. The distance travelled by the bag on the belt during slipping motion, is 

[Take g = 10 m/s2]

A parallel beam of light of wavelength 900 nm and intensity 100 Wm–2 is incident on a surface perpendicular to the beam. The number of photons crossing 1 cm–2 area perpendicular to the beam in one second is
Sand is being dropped from a stationary dropper at a rate of 0.5 kgs–1 on a conveyor belt moving with a velocity of 5 ms–l. The power needed to keep the belt moving with the same velocity will be
The maximum and minimum voltage of an amplitude modulated signal are 60 V and 20 V, respectively. The percentage modulation index will be: