Which of the following statements is (are) NOT true about the emission of the photoelectrons from metallic surfaces?
i. all metallic surfaces emits the same number of photoelectrons in a given light
ii. most metallic surfaces emit the same number of photoelectrons in visible and infra-red light
iii. a metallic surface emits photoelectrons only if the frequency of the incident light is higher than its own characteristics threshold frequency
A galvanometer of resistance 5.0Ω has full-scale deflection for a current of 100mA. How would its range be extended to 1.0A? By placing a resistance of
In a resonance tube experiment, a tube fixed length is closed at one end and several tuning forks of increasing frequency used to obtain resonance at the open end. If the tuning fork with the lowest frequency which gave resonance had a frequency f1 and the next tuning fork to give resonance had a frequency f2, find the ratio \(\frac{f^2}{f^1}\).
Which of the following statements about friction is NOT correct?
