Two stars of masses m1 and m2 are in mutual interaction and revolving in orbits of radii r1 and r2 respectively. The time period of revolution for this system will be? a. b. c. d. Solution: Answer: (b) Let angular velocity will be ω For mass m1, , , ,... View Article
Find the value of Rp in the given circuit? (VZ = 8V) a. 4Ωb. 6Ωc. 3Ωd. 5ΩSolution:Answer: (b)Applying KVL20 - 8 - 2RP = 0RP = 6 Ω... View Article
An electron is accelerated through a voltage of 40 kV. What will be its wavelength? a. 0.061 Åb. 0.011 Åc. 0.021 Åd. 0.161 ÅSolution:Answer: (a)λB = h / P= h / √2meV= = 0.061 Å... View Article
I-V characteristic curve of a diode in a forward bias is given in fig. Find out dynamic resistance a. 212.3 Ωb. 205.3 Ωc. 245.3 Ωd. 233.3 ΩSolution:Answer: (d)Dynamic resistance = ΔV / ΔI= 0.7 V / 3 mA =... View Article
A block is projected up to a rough plane of inclination 30°. If time of ascending is half the time for descending and the coefficient of friction is μ =3/5√n. Then n = Solution:Answer: (n = 3)S = ½ aAtA2 ….. (1)S = ½ aDtD2 ….. (2)From equation (1) and (2) ⇒ 1 + √3μ = 4 -... View Article
A uniform rod of Young’s modulus Y is stretched by two tension forces T1 and T2 such that the rods get expanded to length L1 and L2 respectively. Find the initial length of the rod? a.... View Article
A body is moved from rest along a straight line by a machine delivering constant power. Time taken by the body to travel a distance S is proportional to: a. S1/3 b. S2/3 c. S1/2 d. S1/4 Solution: Answer: (b) Energy supplied in time t sec is, E = P × t Here P represents the power delivered... View Article
An electron having the de Broglie wavelength λ falls on an X-ray tube. The cut-off wavelength of emitted X-ray is a. 2mcλ2 / hb. 2h / mcc. h / mcd. 2mcλ2 / 3hSolution:Answer: (a)De-broglie wavelength, λB = h / PP = h / (λB)Kinetic... View Article
Magnetic susceptibility of a material is 499 & μ0 = 4π × 10−7 SI unit. Then find μr a. 500b. 400c. 300d. 200Solution:Answer: (a)Given, = 499The relative permeability, μr = 1 + = 500... View Article
For a body in pure rolling, its rotational kinetic energy is 1/2 times of its translational kinetic energy. The body should be? a. Solid cylinderb. Ringc. Solid sphered. Hollow sphereSolution:Answer: (a)Given,Rotational K.E = ½ Translational K.E½ Iω2 =... View Article
A sodium lamp in space was emitting waves of wavelength 2880 Å. When observed from a planet, its wavelength was recorded at 2886 Å. Find the speed of the planet? a. 4.25 × 105 m/s b. 6.25 × 105 m/s c. 2.75 × 105 m/s d. 3.75 × 105 m/s Solution: Answer: (b) , ,... View Article
At 45° of the magnetic meridian angle of dip is 30° then find the angle of dip in a vertical plane at 45°? a. tan−1(1/√6)b. tan−1(1/√2)c. tan−1 (1/√4)d. tan−1(1/√3)Solution:Answer: (a)Let the horizontal... View Article
Two satellites of mass MA and MB are revolving around a planet of mass M in radius RA and RB respectively. Then a. TA > TBif RA > RB b. TA> TB if MA> MB c. TA= TB if MA> MB d. TA > TB if RA< RB Solution:Answer: (a)According to... View Article
A plane electromagnetic wave travels in free space. Electric field is [latex]left | vec{E} right |=E_{0}hat{i}[/latex] and magnetic field is represented by [latex]left | vec{B} right |=B_{0}hat{k}[/latex]. What is the unit vector along the direction of propagation of electromagnetic waves? a.... View Article
In photoelectric effect stopping potential is 3V0 for incident wavelength λ0 and stopping potential for incident wavelength 2λ0. Find threshold wavelength. a. 3λ0 b. 2λ0 c. 4λ0 d. 8λ Solution:Answer: (c)KE = hv - WeV = hc / λ - WFor first casee(3Vo) = hc... View Article
Identify the correct graph between PV and T for an ideal gas. Solution:Answer: (c)PV = nRT ⇒ PV=CTTherefore, PV v/s T graph is a straight line.... View Article
The velocities of a particle performing SHM at a distance of x1 and x2 from mean position are v1 and v2, find the time period of oscillation? a. b. c. d. Solution: Answer: (c) , , , , , ,... View Article
Two identical drops of Hg coalesce to form a bigger drop. Find the ratio of the surface energy of a bigger drop to a smaller drop. a. 2 3/2Â b. 3 2/5 c. 2 2/3 d. 5 2/3 Solution: Answer: (c) , ,... View Article
Find the relation between γ(adiabatic constant) and degree of freedom (f). a. f = 2 / γ - 1b. f = γ / γ - 1c. f = γ - 1 /2d. f = γ-1 / γSolution:Answer: (a)We know that,Cv = f R / 2Cp... View Article
Time (T), Velocity (C) and angular momentum (h) is chosen as fundamental quantities instead of mass, length and time. In terms of these, dimension of mass would be a. [M] = [T-1 C-2 h]b. [M] = [T-1 C2 h]c. [M] = [T-1 C-2 h-1 ]d. [M] = [TC-2 h]Solution:Answer: (a)M ∝ Tx cy hz[ M1 L0 T0] = [Tx] [LT-1]y... View Article
