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Figure shows a wave pulse at t = 0. The pulse moves to the right with a speed of 10 cm

Question: Figure (below) shows a wave pulse at t = 0. The pulse moves to the right with a speed... View Article

The equation of a wave travelling on a string stretched along the X-axis is given by

(a) Write the dimensions of A, a and T. (b) Find the wave speed. (c) In which direction is the... View Article

A wave pulse passing on a string with a speed of 40 cm s⁻¹ in the negative x-direction has its maximum at x = 0 at t = 0. Where will this maximum be located at t = 5 s?

Given: A wave pulse passing on a string with a speed of 40 cm s−1 in the negative x-direction has... View Article

A block of mass M is hanging by a string of negligible mass in a car. The speed of the wave in the string 60 m/s. Now the car is accelerated horizontally by an acceleration at the speed of wave in the string is 60.5 m/s. What is a in terms of g?

a) g/5 b) g/10 c) g/20 d) g/30 Answer (c) Speed of wave on string \(\begin{array}{l}v=\sqrt{\frac{T}{\mu }}\end{array} \) wherein, T... View Article

In a semiconductor mobility of electron, i.e. drift velocity per unit applied electric field is 1.6 (S.I unit). Density of electrons is 10¹⁹/m³. (Neglect holes concentration). Resistivity of semiconductor is:

a) 0.4 Ωm b) 2 Ωm c) 4 Ωm d) 0.2 Ωm Answer: (a) \(\begin{array}{l}\sigma =ne\mu \Rightarrow \rho =\frac{1}{ne\mu }=\frac{1}{10^{19}\times... View Article

A capacitor is formed by two square metal-plates of edge a, separated by a distance d. Dielectric of dielectric constants K is filled in the gap as shown in the figure. The equivalent capacitance is

a) \(\begin{array}{l}\frac{k\epsilon _{0}a^{2}lnk}{d(k-1)}\end{array} \) b) \(\begin{array}{l}\frac{k\epsilon _{0}a^{2}lnk}{d(k-2)}\end{array} \) c) \(\begin{array}{l}\frac{k\epsilon _{0}a^{2}lnk}{2d(k-1)}\end{array} \) d) \(\begin{array}{l}\frac{2k\epsilon _{0}a^{2}lnk}{d(k-1)}\end{array} \) Answer: (a) y/d =... View Article

A rod of acted by two equal forces as shown in the figure. The coefficient of thermal expansion of the rod is α and area of cross section is A. When the temperature the rod increased by Δ t. The length of the rod does not change. The young’s modulus Y will be.

a) \(\begin{array}{l}\frac{F}{2A\alpha \Delta T}\end{array} \) b) \(\begin{array}{l}\frac{F}{A\alpha \Delta T}\end{array} \) c) \(\begin{array}{l}\frac{2F}{A\alpha \Delta T}\end{array} \) d) \(\begin{array}{l}\frac{F}{3A\alpha \Delta T}\end{array} \)... View Article

A uniform L shaped rod each of side A is held as shown in the figure. The angle θ such that the rod remains stable will be;

a) tan-1(1/2) b) tan-1(1/3) c) tan-1(2) d) tan-1(1) Answer: (b) Clockwise torque = anti clockwise torque θ = tan-1 (1/3)

If length of resistance wire is increased by 0.5 % keeping the volume constant then change in resistance will be;

a) 0 % b) 1 % c) 0.5 % d) 2 % Answer: (b) \(\begin{array}{l}R = \frac{\rho l\times l}{a\times l}=\frac{\rho... View Article

Two coherent light sources having intensity I₁ and I₂. If the ratio of I_max/I_min is 6 : 1. Find I₁/I₂​​?