Physics
(i) When a tuning fork [vibrating] is held close to ear, one hears a faint hum. The same [vibrating tuning fork] is held such that it's stem is in contact with the table surface, then one hears a loud sound. Explain.
(ii) A man standing in front of a vertical cliff fires a gun. He hears the echo after 3.5 seconds. On moving closer to the cliff by 84 m, he hears the echo after 3 seconds. Calculate the distance of the cliff from the initial position of the man.
Related Questions
Give reasons for the following:
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(i) Clouds appear white.
(ii) Sky appears blue.
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(ii) What are acoustically measurable quantities related to pitch and loudness?
(i) What are superconductors?
(ii) Calculate the current drawn by an appliance rated 110 W, 220 V when connected across 220 V supply.
(iii) Name a substance whose resistance decreases with the increase in temperature.
The diagram below shows the core of a transformer and it's input and output connections
(i) State the material used for the core.
(ii) Copy and complete the diagram of the transformer by drawing input and output coils.