A wavelength of 0.3 m is produced in air and it travels at a speed of 300 m/s. Then it will be an
A. Audible wave
B. Infrasonic wave
C. Ultrasonic wave
D. Microwave
Answer: Option A
Solution(By Examveda Team)
The formula of frequency is: f = c / ë = wave speed c (m/s) / wavelength ë (m), where f: frequency, c: wave speed, and ë: wavelength. As per the question, f = 300/0.3 = 1000 cycles/ seconds = 1000 Hz = 1 KHz.Sound waves with frequencies above 20 KHz are called Ultrasonic; those below 20 Hz are called Infrasonic. Sound waves with frequencies between 20 Hz to 20,000 Hz are called audible waves.
Which of the following terms is not used in the field of physics?
A. Latent heat
B. Nuclear fusion
C. Refractive index
D. Stock value
Radiocarbon is produced in the atmosphere as a result of
A. Collision between fast neutrons and nitrogen nuclei present in the atmosphere.
B. Action of ultraviolet light from the sun on atmospheric oxygen.
C. Action of solar radiations particularly cosmic rays on carbon dioxide present in the atmosphere.
D. Lightning discharge in atmosphere.
It is easier to roll a stone up a sloping road than to lift it vertical upwards because
A. Work done in rolling is more than in lifting.
B. Work done in lifting the stone is equal to rolling it.
C. Work done in both is same but the rate of doing work is less in rolling.
D. Work done in rolling a stone is less than in lifting it.
The absorption of ink by blotting paper involves:
A. Viscosity of ink
B. Capillary action phenomenon
C. Diffusion of ink through the blotting
D. Siphon action
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