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Statement I: A speech signal of 2 kHz is used to modulate a carrier signal of 1 MHz. The bandwidth requirement for the signal is 4 kHz. Statement II: The side band frequencies are 1002 kHz and 998 kHz. In the light of the above statements, choose the correct answer from the options given below:

a. Both statement I and statement II are false b. Statement I is false but statement II is true c.... View Article

A diatomic gas, having C_p = (7/2)R and C_v= (5/2)R, is heated at constant pressure. The ratio dU : dQ :

a. 3 : 7 : 2 b. 5 : 7 : 2 c. 5 : 7 : 3 d. 3... View Article

A student is performing the experiment of resonance column. The diameter of the column tube is 6 cm. The frequency of the tuning fork is 504 Hz. Speed of the sound at the given temperature is 336 m/s. The zero of the metre scale coincides with the top end of the resonance column tube. The reading of the water level in the column when the first resonance occurs is:

a. 13 cm b. 14.8 cm c. 16.6 cm d. 18.4 cm Answer: (b) λ = v/f = 336/504 =... View Article

A solid sphere of radius R gravitationally attracts a particle placed at 3R from its centre with a force F₁. Now a spherical cavity of radius R/2 is made in the sphere (as shown in figure) and the force becomes F₂. The value of F₁: F₂ is:

A solid sphere of radius R gravitationally attracts a particle placed at 3R from its centre with a force F1.... View Article

A 5V battery is connected across the points X and Y. Assume D1 and D2 to be normal silicon diodes. Find the current supplied by the battery if the +ve terminal of the battery is connected to point X.

A 5V battery is connected across the points X and Y. Assume D1 and D2 to be normal silicon diodes.... View Article

A signal of 0.1 kW is transmitted in a cable. The attenuation of cable is -5 dB per km and cable length is 20 km. The power received at receiver is 10^-xW. The value of x is ______.

[Gain in dB = 10 log10(P0/Pi)] Answer: 8 Power of signal transmitted: Pi = 0.1 Kw = 100w Rate of... View Article

An electromagnetic wave of frequency 3 GHz enters a dielectric medium of relative electric permittivity 2.25 from vacuum. The wavelength of this wave in that medium will be _______ ×10^-2 cm.

Answer: 667 εr = 2.25 Assuming non-magnetic material ⇒ μr = 1 Hence refractive index of the medium n =... View Article

a series lcr circuit is designed to resonate at an angular frequency omega0 equal 105rad s the circuit draws 16W power from 120 v source at resonance the value of resistance in the circuit is omega

Answer: 900 P = V2/R 16 = 1202/R ⇒ R = 14400/16 ⇒ R = 900 Ω

The root mean square speed of molecules of a given mass of a gas at 27⁰C and 1 atmosphere pressure is 200 ms^-1. The root mean square speed of molecules of the gas at 127⁰C and 2 atmosphere pressure is x/√3 ms^-1. The value of x will be __________.

Answer: 400 m/s Vrms = √(3RT1/M0) 200 = √(3R×300/M0) ….(1) Also, x/√3 = √(3R×400/M0) …(2) (1)÷(2) 200/(x/√3) = √(300/400) =... View Article

Two solids A and B of mass 1 kg and 2 kg respectively are moving with equal linear momentum. The ratio of their kinetic energies (K.E.)_A : (K.E.)_B will be A/1. So the value of A will be ________.

Answer: 2 Given that, M1/M2 = 1/2 we know that K = p2/2M K1/K2 = (p2/2M1 )×2M2/p2 K1/K2 = M2/M1... View Article

A point charge of +12 μC is at a distance 6 cm vertically above the centre of a square of side 12 cm as shown in figure. The magnitude of the electric flux through the square will be _____ ×10³ Nm²/C.

A point charge of +12 μC is at a distance 6 cm vertically above the centre of a square of... View Article

A uniform thin bar of mass 6 kg and length 2.4 meter is bent to make an equilateral hexagon. The moment of inertia about an axis passing through the centre of mass and perpendicular to the plane of hexagon is ______×10^-1 kg m²

A uniform thin bar of mass 6 kg and length 2.4 meter is bent to make an equilateral hexagon. The... View Article

Two cars are approaching each other at an equal speed of 7.2 km/hr. When they see each other, both blow horns having frequency of 676 Hz. The beat frequency heard by each driver will be ________ Hz. [Velocity of sound in air is 340 m/s.]

Two cars are approaching each other at an equal speed of 7.2 km/hr. When they see each other, both blow... View Article

A cylindrical wire of radius 0.5 mm and conductivity 5×10⁷ S/m is subjected to an electric field of 10 mV/m. The expected value of current in the wire will be x³π mA. The value of x is ____.

Answer: 5 We know that J = σE ⇒ J = 5×107×10×10-3 ⇒ J = 50×104 A/m2 Current flowing; I... View Article

A uniform metallic wire is elongated by 0.04 m when subjected to a linear force F. The elongation, if its length and diameter is doubled and subjected to the same force will be ________ cm.

A uniform metallic wire is elongated by 0.04 m when subjected to a linear force F. The elongation, if its... View Article

A particle is projected with velocity v₀ along x-axis. A damping force is acting on the particle which is proportional to the square of the distance from the origin i.e. ma = -αx². The distance at which the particle stops:

a. (2v0/3α)1/3 b. (3v02/2α)1/2 c. (3v02/2α)1/3 d. (2v02/3α)1/2 Answer: Bonus a = vdv/dx \(\begin{array}{l}\int_{V_{i}}^{V_{f}} V\: dv = \int_{X_{i}}^{X_{f}}\: adx\end{array} \)... View Article

Which of the following equations represents a travelling wave?

a. \(\begin{array}{l}y = Ae^{x^{2}} (vt + \Theta )\end{array} \) b. y = A sin(15x – 2t) c. y = Aex cos(ωt... View Article

A soft ferromagnetic material is placed in an external magnetic field. The magnetic domains:

a. decrease in size and changes orientation. b. may increase or decrease in size and change its orientation. c. increase... View Article

Two electrons each are fixed at a distance ‘2d’. A third charge proton placed at the midpoint is displaced slightly by a distance x (x<<d) perpendicular to the line joining the two fixed charges. Proton will execute simple harmonic motion having angular frequency:

(m = mass of charged particle) a. (q2/2πε0md3)1/2 b. (πε0md3/2q2)1/2 c. (2πε0md3/q2)1/2 d. (2q2/πε0md3)1/2 Answer: (a) Restoring force on proton:-... View Article

The de Broglie wavelength of a proton and α-particle are equal. The ratio of their velocities is:

a. 4:2 b. 4:1 c. 1:4 d. 4:3 Answer: (b) Sol. From De-Broglie’s wavelength:- λ = h/mv Given λP =... View Article

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