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Physics

A ray of light incident at an angle θ on a refracting face of a prism emerges from the other face normally. If the angle of the prism is 5o and the prism is made of a material of refractive index 1.5, the angle of incidence is
a) 7.5o
b) 5o
c) 15o
d) 2.5o

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Answer: a) 7.5o The distance between the refracting surfaces is negligible with thin prisms, thus the prism angle (A) is very small. Because A = r1 + r2, if A is tiny, both r1 and r2 will be little...

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First, a set of n equal resistors of R each are connected in series to a battery of emf E and internal resistance R. A current I is observed to flow. Then the n resistors are connected in parallel to the same battery. It is observed that the current is increased 10 times. What is ‘n’?

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The current is represented as I = E/R+nR when the resistors are connected in series. Current is expressed as 10I = E/(R+R/n) when the resistors are connected in parallel. We get n = 10 by solving...

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In the figure, two positive charges q2 and q3 fixed along the y-axis, exert a net electric force in the +x direction on a charge q1 fixed along the x-axis. If a positive charge Q is added at (x,0) the force on q1 a) shall increase along the positive x-axis b) shall decrease along the positive x-axis c) shall point along the negative x-axis d) shall increase but the direction changes because of the intersection of Q with q2 and q3

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the correct option is a) shall increase along the positive x-axis.

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a) How many astronomical units (AU) make 1 parsec?
b) Consider the sun like a star at a distance of 2 parsec. When it is seen through a telescope with 100 magnification, what should be the angular size of the star? Sun appears to be (1/2) degree from the earth. Due to atmospheric fluctuations, eye cannot resolve objects smaller than 1 arc minute.

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a) 1 parsec is the distance at which 1 AU long arc subtends an angle of 1s, according to the definition. Using the definition, we can write, 1 parsec = (3600)(180)/π AU = 206265 AU = 2 × 105 AU b)...

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A particle is in linear simple harmonic motion between two points, A and B, 10 \mathrm{~cm} apart. Take the direction from A to B as the positive direction and give the signs of velocity, acceleration and force on the particle when it is
(a) at 3 \mathrm{~cm} away from A going towards \mathrm{B}, and
(b) at 4 \mathbf{c m} away from B going towards A.

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(a) Positive, Positive, Positive From the end $A$, the particle is travelling toward point 0. This motion is going from $A$ to $B$, which is the standard positive direction. As a result, the...

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A mild steel wire of length 1.0 \mathrm{~m} and cross-sectional area 0.50 \times 10^{-2} \mathrm{~cm}^{2} is stretched, well within its elastic limit, horizontally between two pillars. A mass of 100 \mathrm{~g} is suspended from the mid-point of the wire. Calculate the depression at the midpoint.

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Water pressure at the bottom is given as, $p=1000 a t m=1000 \times 1.013 \times 10^{5}$ Pa $p=1.01 \times 10^{8} \mathrm{~Pa}$ Initial volume of the steel ball is given as $V=0.30 \mathrm{~m}^{3}$...

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