A tuning fork of frequency 580 Hz is employed to produce transverse waves on a long rope. The distance between the nearest crusts is found to be 20 cm. The velocity of the wave is

• 58 ms^-1

• 580 ms^-1

• 116 ms^-1

• 29 ms^-1

A heavy brass sphere is hung from a weightless inelastic spring and as a simple pendulum its time period of oscillation is T. When the sphere is immersed in a non-viscous liquid of density 1/10 that of brass, it will act as a simple pendulum of period

• T

• $\frac{10}{9} \mathrm{T}$

• $\sqrt{\left(\frac{9}{10}\right) } \mathrm{T}$

• $\sqrt{\left(\frac{10}{9}\right) } \mathrm{T}$

The distance travelled by a sound wave when a tuning fork completes 25 vib in 16.5 m. If the frequency of the tuning fork is 500 Hz, find the velocity of sound.

• 350 ms^-1

• 330 ms^-1

• 300 ms^-1

• 450 ms^-1

Two instruments having stretched strings are being played in unison. When the tension of one of the instruments is increased by 1 %, 3 beats are produced in 2s. The initial frequency of vibration of each wire is

• 300 Hz

• 500 Hz

• 1000 Hz

• 400 Hz

The capacitors A and B have identical geometry. A material with a dielectric constant 3 is present between the plates of B. The potential difference across A and B are respectively

• 2.5 V, 7.5 V

• 2 V, 8 V

• 8 V, 2 V

• 7.5 V, 2.5 V

An electric bulb is marked 100 W, 230 V. If the supply voltage drops to 115 V, what is the total energy produced by the bulb in 10 min ?

• 30 kJ

• 20 kJ

• 15 kJ

• 10 kJ

37.

A circular coil carrying a current has a radius R. The ratio of magnetic induction at the centre of the coil and at a distance equal to $\sqrt{3}\mathrm{R}$ from the centre of the coil on the axis is

• 1 : 1

• 1 : 2

• 8 : 1

• 1 : 8

The examples of diamagnetic, paramagnetic and ferromagnetic materials are respectively

• copper, aluminium, iron

• aluminium, copper, iron

• copper, iron, aluminium

• aluminium, iron, copper

In the Wheatstone's bridge shown below, in order to balance the bridge we must have

• R₁ = 3 Ω, R₂ = 3 Ω

• R₁ = 6 Ω, R₂ = 1.5 Ω

• R₁ = 1.5 Ω, R₂ = any finite value

• R₁ = 3 Ω, R₂ = any finite value

Four 10 F capacitors are connected to a 500 V supply as shown in the figure. The equivalent capacitance of the network is

• 40 μF

• 20 μF

• 13.3 μF

• 10 μF