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A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency

Time period is defined as the time required to complete one oscillation. Frequency is defined as the number of oscillations per unit time. Time =... View Article

Fill in the blanks with suitable words. (a) Time taken by an object to complete one oscillation is called . (b) Loudness is determined by the of vibration. (c) The unit of frequency is (d) Unwanted sound is called . (e) The shrillness of a sound is determined by the __ of vibration.

(a) Time taken by an object to complete one oscillation is called time period. (b) Loudness is determined by amplitude of vibration. (c) The unit... View Article

In the following statements, tick ‘T’ against those which are true, and ‘F’ against those which are false. (a) Sound cannot travel in vacuum. (T/F) (b) The number of oscillations per second of a vibrating object is called its time period. (T/F) (c) If the amplitude of vibration is large, sound is feeble. (T/F) (d) For human ears, the audible range is 20 Hz to 20,000 Hz. (T/F) (e) The lower the frequency of vibration, the higher is the pitch. (T/F) (f) Unwanted or unpleasant sound is termed as music. (T/F) (g) Noise pollution may cause partial hearing impairment. (T/F)

(a) Sound cannot travel in a vacuum. (True) Explanation: Sound needs a medium to travel. (b) The number of oscillations per second of a vibrating... View Article

Voice of which of the following is likely to have a minimum frequency? (a) Baby girl (b) Baby boy (c) A man (d) A woman

Answer is: (c) The man The voice of a man is of lower pitch as compared to the voice of a baby girl, baby boy or a woman. Since frequency of... View Article

Choose the correct answer. Sound can travel through (a) gases only (b) solids only (c) liquids only (d) solids, liquids and gases

Answer is option (d) Solid, liquid and gas. Sound travels more quickly through solids than through liquids and gases because the molecules of... View Article

Two children are at opposite ends of an aluminum rod. One strikes the end of the rod with a stone. Find the ratio of times taken by the sound wave in the air and in aluminum to reach the second child.

Let the distance between the two children be d Also let the time taken by sound to reach other child via air be t1 and via aluminium rod be t2.... View Article

Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen, why?

Thunder is heard few seconds later after the flash because speed of light in atmosphere for air is 3 × 108 ms-2which is very high, as... View Article

A person is listening to a tone of 500 Hz sitting at a distance of 450 m from the source of the sound. What is the time interval between successive compressions from the source?

Given - n=500Hz the time interval between two successive compressions or rarefactions is called, time period of wave, which is given by , T = 1/n... View Article

Which wave property determines (a) loudness, (b) pitch?

(a) The loudness or softness of a sound is determined by its amplitude. (b) Pitch of the sound is determined by its frequency. The pitch of a... View Article

What are the immunization programs available at the nearest health center in your locality? Which of these diseases are the major health problems in your area?

A process by which a person becomes protected against a disease through vaccination. Immunity (protection) by immunization is similar to the... View Article

What precautions can you take in your school to reduce the incidence of infectious diseases?

The most important way to reduce the spread of infections is handwashing - frequently wash hands with soap and water, if unavailable use... View Article

What are the different means by which infectious diseases are spread?

Infectious diseases can spread in a variety of ways: through the air, from direct or indirect contact with another person, soiled objects, skin... View Article

Why are we normally advised to take bland and nourishing food when we are sick?

During sickness the body becomes weak, and the digestive system does not work properly. So easily digested food need to be taken during this... View Article

In which of the following case do you think the long-term effects on your health are likely to be most unpleasant? a) if you get jaundice b) if you get lice c) if you get acne. Why?

Lice and acne will not cause any long-term effects on the human body. However, the effects of jaundice will be long-term and most... View Article

List any three reasons why you would think that you are sick and ought to see a doctor. If only one of these symptoms were present, would you still go to the doctor? Why or why not?

Three reasons why we would think that we are sick and ought to see a doctor are: (a). Headache (b). Fever (c). Cold and cough We usually not... View Article

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