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18 Aug 2021: The Hindu Analysis

UPSC Current Affairs Preparation: The Hindu Analysis Watch expert analysis of ‘The Hindu’ dated 18th Aug 2021. Important news and views to boost... View Article

In a magnesium rod of area 3m², current I = 5A is flowing angle of 60⁰ from the axis of the rod. The resistivity of the material is 44 × 10⁻² ohm x m. Find an electric field inside the rod

a. 0.567b. 0.367c. 0.667d. 0.767Solution: Answer: (b) E = 0.367... View Article

A body of mass m emits a photon of frequency v, then loss in its internal energy?

a.... View Article

Four planks are arranged in a lift going upwards with an acceleration of 0.2 m/s²as shown in the figure. Find the normal reaction applied by the lift on 10 kg block:

a. 500b. 700c. 672d. 800Solution: Answer: (b)N - 70g = 70 x 0.2N = 70 (g + 0.2)N = 700... View Article

A particle of mass moving with a speed v collide elastically with the end of a uniform rod of mass M and length L perpendicularly as shown in the figure. If the particle comes to rest after collision, find the value of m/M.

a. 1/3 b. 1/2 c. 1/4 d. 1/5 Solution: Answer: (A) Applying conservation of angular momentum about the Centre of mass of rod ω = 6mu/ML... View Article

A vehicle moving with velocity v and releasing the sound of frequency 400 Hz. Listening to the reflected sound from a wall of frequency 500 Hz. Find the velocity of vehicle

a. 36.67 m/sb. 30.12 m/sc. 22.37 m/sd. 20.25 m/sSolution: Answer: (a)Frequency received by wall ⇒ v = 330/9 = 36.67 m/s... View Article

The wavenumber of the spectral line in the emission spectrum of hydrogen will be equal to 8/9 times of the Rydberg’s constant. Then the electron jumps from

a. 5 → 2b. 5 → 3c. 3 → 1d. 4 → 2Solution: Answer: (c)... View Article

A ball of charge to mass ratio of 8 μC/g is placed at a distance of 10 cm from the ball. An electric field of 100 N/m is switched on in the direction of the wall. Find the time period of its oscillations. Assume all collisions are elastic.

a. 1 secb. 2 secc. 3 secd. 4 secSolution: Answer: (a) As the electric field is switched ON, the ball first strikes the wall and returns back.One... View Article

A travelling wave is found to have the displacement by y = 1/(1+x)²at t = 0, after 3 sec the wave pulse is represented by equation y = 1/1+(1+x)². The velocity of the wave is:

a. 1 m/sb. 1/3 m/sc. 2/3 m/sd. ¼ m/sSolution: Answer: (b)Displacement of wave, Δx = 1 m⇒ v x t = 1t = 1/v3 =1/vv = 1/3 m/s... View Article

A conducting rod of length l is moving perpendicular to the magnetic field. The rod moves from 0 to 2b while the field exists only from 0 to b. Find the graph for emf and power dissipated w.r.t x.

Solution: Answer: From the given figure it is clear that the field exists from 0 to b only, therefore, the given conductor will experience a... View Article

A spring with natural length l₀ has a tension T₁ when its length is l₁ and the tension is T₂ when its length is l₂. The natural length of spring will be:

a.... View Article

Consider a body of 800 kg moving with a maximum speed v on a road banked at θ= 30⁰ given cos 30⁰ = 0.87. Find the normal reaction on the body. Coefficient of friction μ_s = 0.2. [Take radius, r = 10 m]

a. 10. 4 kNb. 12.6 kNc. 11.6 kNd. 8.3 kNSolution: Answer: (a)Since the circular motion is such that v = vmax the tendency of the body is to move... View Article

For an element decaying through simultaneous reaction, the half-life for the respective decaying path is 1400 S and 700 S. Find the time taken when the number of atoms becomes N₀/3 in the element sample. (N₀ is the initial number of atoms in sample)

a. (1400/5) In 3b. (1400/3) In 3c. (1400/3)ln 2d. (700/3)ln 2Solution: Answer: (b)N = N0et/τN0/3 = N0et/τTaking natural log on both... View Article

An object moves from the earth’s surface to the surface of the moon. The acceleration due to gravity on the earth’s surface is 10 m/s²…..

Question: An object moves from the earth’s surface to the surface of the moon. The acceleration due to gravity on the earth’s surface... View Article

If [latex]\vec{A}.\vec{B}=\vec{A}\times \vec{B}[/latex] find [latex]\left | \vec{A}-\vec{B} \right |[/latex]

a. A - Bb.... View Article

In the circuit shown, find the current through the Zener diode.

a. 5 mAb. 1 mAc. 15 mAd. 25 mASolution: Answer: (d)Since 2000 Ω is parallel to the Zener diodeSo, the current passing through it as shown... View Article

Deuteron and alpha particles having the same KE in a magnetic field. If the ratio of the radius of Deuteron and alpha particle is x√2. Then x =

a. 5b. 8c. 3d. 1Solution: Answer: (d)KE = B2q2r2/2mAs B and KE are the samer2 ∝ m/q2 ⇒ r =√m/q... View Article

Bird is flying in north-east direction with or v = 4√2 m/s with respect to the wind and the wind blowing from north to south with speed 1 m/s. Find the magnitude of the displacement of the bird in 3 sec.

a. 5 mb. 15 mc. 10 md. 20 mSolution: Answer: (b)... View Article

A charge Q is divided into q and (Q – q). If Q/q = x, such that the repulsion between them is maximum, find x.

a. 1b. 2c. 3d. 4Solution: Answer: (b) 2As we know, F = (k(Q−q)q) /d2For F to be maximum,dE/dq = 0⇒ Q − 2q = 0⇒ Q/q =... View Article

An electron is projected into a magnetic field of B = 5 × 10⁻³T and rotates in a circle of radius of R = 3mm. Find the work done by the force due to the magnetic field.

a. 0 Jb. 15 mJc. 14 mJd. 20 mJSolution: Answer: (a) The work done by the force due to the magnetic field is 0.... View Article