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A small hole of an area of cross-section 2mm² is present near the bottom of a fully filled open tank of height 2 m. Taking g=10m/s², the rate of flow of water through the open hole would be nearly

a) 2.23 x 10-6 m3/s-1 b) 6.4 x 10-6 m3/s-1 c) 12.6 x 10-6 m3/s-1 d) 8.9 x 10-6 m3/s-1 The correct answer is c) 12.6 x 10-6 m3/s-1 The... View Article

The position-time (x-t) graphs for two children A and B returning from their school O to their homes P and Q respectively are shown in Fig. above. Choose the correct entries in the brackets below:

(a) (A/B) lives closer to the school than (B/A) (b) (A/B) starts from the school earlier than (B/A) (c) (A/B) walks faster than (B/A) (d) A... View Article

A 0.1m long conductor carrying a current of 50A is perpendicular to a magnetic field of 1.21 mT. The mechanical power to move the conductor with a speed of 1ms⁻¹ is

a) 0.25 mW b) 6.25 mW c) 0.625 W d) 1 W Answer: b) 6.25 mW Solution: Mechanical power required = electrical power expended due to the... View Article

A straight tunnel is dug into the earth as shown in the figure at a distance d from its
centre. A ball of mass m is dopped from one of its ends.The time it takes to reach the other end is approximately

a) 42 min b) 84 min c) 84 (d/R) min d) 42 (d/R) min Answer: a) 42 min Solution: The gravitational field inside the earth's surface g=... View Article

The wavelengths of 60 cm and 61 cm, produces 9 beats/ second. The velocity of sound is (approximately)

(1) 330 m/s (2) 335 m/s (3) 340 m/s (4) 325 m/s Answer: (1) 330 m/s Solution: Number of beats produced per second v1 - v2 =... View Article

In the circuit shown, the reading of the ammeter (ideal) is the same with both switches open as with both closed. Find the value of resistance R in ohm

Answer: 600 Ω Solution: i0 = 1.5/[300 + (100R/(100 + R)] i1 = i0 (R/(100 + R)) i1 = 1.5/[300 + (100R/(100 + R))] (R/100 + R) i = i1 1.5/400... View Article

A ring of radius R is having two charges q and 2q distributed on its two half parts. The electric potential at a point on its axis at a distance of 2√2 from its centre is (k= 1/4πε₀)

a) 3kq/R b) kq/3R c) kq/R d) kq/√3R Answer; c) kq/R Solution: r = √R2 + (2√2R)2 r = 3R vp = kqnet/r =... View Article

To a fish underwater, viewing obliquely a fisherman standing on the bank of a lake, the man looks

a) taller than what he actually is b) shorter than what he actually is c) The same height as he actually is d) Depends on the obliquity... View Article

In the figure, the blocks A, B and C of mass m each have acceleration a₁, a₂ and a₃ respectively. F₁ and F₂ are external forces of magnitude 2 mg and mg respectively. Then

(A) a1 = a2 = a3 (B) a1 > a3 > a2 (C) a1 = a2 , a2 > a3 (D) a1 > a2 , a2 = a3 Answer: (B) a1 > a3 > a2 Solution: Case... View Article

A person wishes to distinguish between two pillars located at a distance of 11 km. What should be the minimum distance between these pillars (resolving power of the normal human eye is 1′)?

a) 1 m b) 3.2 m c) 0.5 m d) 5 m Answer: b) 3.2 m Solution: Limit of resolution of human eye is θ = 1' = 10/60 = π/(60 x 180)radian If x... View Article

A transparent slab of thickness d has a refractive index n(z) that increases with z. Here z is the vertical distance inside the slab, measured from the top. The slab is placed between two media with uniform refractive indices n₁ and n₂ (>n₁), as shown in the figure. A ray of the light incident with angle θ_i from medium 1 and emerges in medium 2 with refraction angle θ_f with lateral displacement l.Which of the following statement(s) is (are) true?

a) l is independent of n2 b) n1 sinθi = n2sinθf c) l is dependent on n(z) d) n1 sin θi = (n2 - n1) sinθf Answer: a, b, c Solution: n1sinθi... View Article

A motorcycle is travelling on a curved track of radius 500m. If the coefficient of friction between road and tyres is 0.5, the speed avoiding skidding will be a) 50 m/s b) 75 m/s c) 25 m/s d) 35 m/s

a) 50 m/s b) 75 m/s c) 25 m/s d) 35 m/s Answer: a) 50 m/s Solution: Velocity in a curved track given is V = √μrg V=√0.5×500×10 Therefore,... View Article

What is the approximate peak value of an alternating current producing four times the heat produced per second by a steady current of 2A in a resistor?

a) 2.8 A b) 4.0 A c) 5.6 A d) 8.0 A Answer:c) 5.6 A Solution: Irms = 2 x Isteady ------(1) Also Irms = Imax/√2 --------(2) From (1) and... View Article

A crew of scientists has built a new space station.The space station is shaped like a wheel of radius R with essentially all its mass M at the rim.When the crew arrives the station will be set rotating at a rate that causes an object at the rim to have radial acceleration g thereby simulating Earth’s surface gravity.This is accomplished by two small rockets each with thrust T newtons mounted on the station’s rim. How long a time t does one need to fire the rockets to achieve the desired condition?

Answer: t = √gR (M/2T) Solution: In order to simulate a gravity of g, we need the centripetal acceleration to be equal to g g = ω2R ω = √g/R... View Article

What is 32 degrees Celsius in Fahrenheit?

Answer: 89.6 degrees Fahrenheit Solution: The formula to convert Celsius to Fahrenheit is F = [ C × (9/5) + 32 ] Given, C = 32... View Article

A capacitor of 4 μF is connected as shown in the circuit. The internal resistance of the battery is 0.5 Ω. The amount of charge on the capacitor plates will be

a) 0 b) 4 μC c) 16 μC d) 8 μC Answer: d) 8 μC Solution: From the figure, there is no current flow through 10Ω resistance because of the... View Article

The circuit shown in the figure consists of a battery of emf ε =10V; a capacitor of capacitance C=1.0 µF and three resistors of values R₁ =2 Ω, R₂ =2 Ω and R₃ =1 Ω. Initially, the capacitor is completely uncharged and the switch S is open. The switch S is closed at t=0

(A) The current through resistor R3 at the moment the switch closed is zero. (B) The current through resistor R3 a long time after the switch... View Article

The flux linked with a circuit is given by ϕ=t³ +3t−7. The graph between time (x-axis) and induced emf (y-axis) will be

a) a straight line through the origin b) Straight line through positive intercept c) Straight line through negative intercept d) Parabola... View Article

Which of the following graph represent the variation of magnetic flux density b with distance r for a straight long wire carrying an electric current?

Which of the following graph represent the variation of magnetic flux density b with distance r for a straight long wire carrying an electric... View Article

A ball is projected horizontally with velocity 4 m/s from the top of a building 19.6 m high. The distance of the point from the bottom of the building where ball will hit the ground is (g = 9.8 ms^–2)

A ball is projected horizontally with velocity 4 m/s from the top of a building 19.6 m high. The distance of the point from the bottom of the... View Article

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