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For a body moving with relativistic speed, if the velocity is doubled, then

1) its linear momentum is doubled 2) its linear momentum will be less than double 3) its linear momentum will be more than double 4) its... View Article

Two electrons are moving in an opposite direction with speeds of 0.8 c and 0.4 c, where c is the speed of light in a vacuum. Then, the relative speed is about

1) 0.4 c 2) 0.8 c 3) 0.9 c 4) 1.2 c Answer: 3) 0.9 c Solution: Relativity addition formula, Vrel = 1.2 c/(1 + 0.32) = 1.2... View Article

A laser device produces amplification in the

1) microwave region 2) ultraviolet or visible region 3) infrared region 4) None of the above Answer: 2) ultraviolet or visible... View Article

In a ruby laser, the stimulated emission is due to the transition from

1) metastable state to any lower state 2) any higher state to lower state 3) metastable state to ground state 4) any higher state to ground... View Article

Which of the following is not the main characteristic of laser beam?

1) Highly intense 2) Highly directional 3) Highly monochromatic 4) incoherent Answer: 4) incoherent Solution: The laser light... View Article

A laser beam is used for carrying out surgery because it

1) is highly monochromatic 2) is highly coherent 3) is highly directional 4) can be sharply focused Answer: 4) can be sharply... View Article

If the area to be covered for TV telecast is doubled, then the height of the transmitting antenna (TV tower) will have to be

1) doubled 2) halved 3) quadrupled 4) kept unchanged Answer: 1) doubled Solution: The is given by d = √2Rh... View Article

The waves relevant to telecommunication are

1) visible light

2) infrared

3) ultraviolet

4) microwave

5) None of the above

Answer: 4) microwave Solution: Microwaves are used in telecommunication since their frequency is high enough to carry the information.... View Article

In coaxial cable the material used as space is

1) teflon (or) polyethylene 2) glass or mica 3) a gaseous medium 4) glass 5) mica Answer: 1) Teflon (or) polyethylene Solution:... View Article

Which frequency range is used for optical communication?

1) 100000 GHz to 400000 GHz 2) 200 kHz to 3 MHz 3) 30000 GHz to 6000 GHz 4) None of the above Answer: 1) 100000 GHz to 400000 GHz... View Article

If an equation of a tangent to the curve, y = cos(x + y), -1 ≤ x ≤ 1+ π, is x + 2y = k then k is equal to :

(a) 1 (b) 2 (c) π/2 (d) π/4 Solution: Let y = cos (x + y) ..(i) Differentiate w.r.t.x dy/dx = -sin (x+y)(1 + dy/dx) ..(i)... View Article

A lamp is 50 ft. above the ground. A ball is dropped from the same height from a point 30 ft. away from the light pole. If ball falls a distance s = 16t²ft. in t seconds, then the speed of the shadow of the ball moving along the ground 1/2 s later is

(a) - 1500 ft/s (b) 1500 ft/s (c) - 1600 ft/s (d) 1600 ft/s Solution: At time t, ball drops 16t2 ft. distance. So y = 50 - 16t2 Point A... View Article

The velocity v of a particle at any instant t moving in a straight line is given by v = s + 1 where s metre is the distance travelled in t seconds. What is the time taken by the particle to cover a distance of 9m?

(a) 1 s (b) (log 10) s (c) 2 (log 10) s (d) 10 s Solution: Given v = s+1 Velocity = ds/dt => s+1 = ds/dt =>... View Article

What is the slope of the tangent to the curve x = t² + 3t – 8, y = 2t² – 2t – 5 at t = 2?

(a) 7/6 (b) 6/7 (c) 1 (d) 5/6 Solution: Given x = t2 + 3t - 8 dx/dt = 2t + 3 y = 2t2 - 2t - 5 dy/dt = 4t - 2... View Article

What is the slope of the tangent to the curve y = sin^-1 (sin²x) at x = 0?

(a) 0 (b) 1 (c) 2 (d) None of these Solution: Given y = sin-1 (sin2x) Differentiate w.r.t.x dy/dx =... View Article

The equation of one of the tangents to the curve y = cos (x +y), -2π ≤ x ≤ 2π that is parallel to the line x + 2y = 0, is

(a) x + 2y = 1 (b) x + 2y = π/2 (c) x + 2y = π/4 (d) None of these Solution: Given y = cos(x +y) dy/dx = -sin (x+y)... View Article

Let f and g be functions from the interval [0, ∞) to the interval [0, ∞), f being an increasing and g being a decreasing function. If f{g(0)} = 0 then

(a) f{g(x)} ≥ f{g(0)} (b) g{f (x)} ≤ g{f (0)} (c) f {g(2)} = 7 (d) None of these Solution: f '(x) > 0 if x ≥ 0... View Article

The largest area of a trapezium inscribed in a semicircle of radius R, if the lower base is on the diameter, is

(a) 3√3R2/4 (b) (√3/2)R2 (c) (3√3/8)R2 (d) R2 Solution: ABCD is the trapezium. Centre of semicircle is O. ∠ADB = 900 (angle in a... View Article

If at any instant t, for a sphere, r denotes the radius, S denotes the surface area and V denotes the volume, then what is dV/dt equal to?

(a) ½ S (dr/dt) (b) ½ r (dS/dt) (c) r dS/dt (d) ½ r2 dS/dt Solution: Surface area of sphere S = 4πr2... View Article

The function f(x) = 2 log (x – 2) – x² + 4x + 1 increases on the interval

(a) (1, 2) (b) (2, 3) (c) (5/2, 3) (d) (2, 4) Solution: Given f(x) = 2 log (x - 2) - x2 + 4x + 1 Differentiate... View Article

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