11.

Under the same conditions of temperature and presssure, the velocity of sound in oxygen and hydrogen are v_o and v_H. Then

• v_o = 4v_H

• v_H = 4v_o

• v_o = v_H

• v_H = 16v_o

The load versus elongation graph for four wires of the same materials is shown in the figure. The thinnest wire is represented by the line

• OC

• OD

• OA

• OB

One kilogram of ice at 0°C is mixed with one kilogram of water at 80°C. The final temperature of the mixture is (take : specific heat of water = 4200 Jkg^-1 K^-1, latent heat of ice = 336 kJ kg^-1).

• 40°C

• 60°C

• 0°C

• 50°C

A Carnot's engine is made to work between 200°C and 0°C first and then between 0°C and − 200°C. The ratio of efficiencies of the engine in the two cases is

• 1 : 1.73

• 1.73 : 1

• 1 : 2

• 1 : 1

Forty one tuning forks are arranged in increasing order of frequencies such that every fork gives 5 beats with the next. The last fork has a frequency that is double the frequency of the first fork is

• 210

• 400

• 205

• 200

In a stationary wave all the particles

• in the region between two nodes vibrate in same phase

• on either side of a node vibrate in same phase

• of the medium vibrate in same phase

• in the region between two antinodes vibrate in same phase

A cylindrical tube open at both ends, has a fundamental frequency f₀ in air. The tube is dipped vertically into water such that half of its length is inside water. The fundamental frequency of the air column now is

• f₀

• $\frac{3{\mathrm{f}}_0}{4}$

• 2f₀

• $\frac{{\mathrm{f}}_0}{2}$

A man x can hear upto 10 kHz and another man y upto 2 kHz. A note of frequency 500 Hz is produced before them from a stretched string then both will hear sounds of

• different pitch but same quality

• same pitch but different quality

• same pitch and same quality

• different pitch and different quality

The equation $\mathrm{y} = \mathrm{A} {\cos }^2 \left[2\mathrm{\pi nt} - 2\mathrm{\pi }\frac{\mathrm{x}}{\mathrm{y}}\right]$ represents a wave with

• amplitude A/2, frequency 2n and wavelength λ

• amplitude A/2, frequency 2n and wavelength $\frac{\mathrm{\lambda }}{2}$

• amplitude A, frequency n and wavelength λ

• amplitude A, frequency 2n, wavelength 2λ

A light points fixed to one prong of a tuning fork touches a vertical plate. The fork is set vibrating and the plate is allowed to fall freely. If eight oscillations are counted when the plate falls through 10 cm, the frequency of the tuning fork is

• 280 Hz

• 360 Hz

• 56 Hz

• 560 Hz