The frequency and work function of an incident photon are n andππ. If f0 is the threshold frequency, then necessary condition for the emission of photo electron is:
Light of frequency 2 times the threshold frequency is incident on the metalsurface. Ifthe frequency is by quartered and intensity is doubled, the photoelectric becomes
According to Bohrβs theory, a line in the Ballmer series arises when the electron jumps from any of the higher orbits to the orbit with quantum number:
Light of frequency 1.5 times the threshold frequency is incident on a photo sensitive material. If the frequency is halved and intensity is doubled the photo electric current becomes
A rigid uniform bar of length 2.4 m is pivoted horizontally at its mid-point, weights are hung from two points
of the bar as shown in diagram. To maintain horizontal equilibrium, a couple is applied to the bar:
What is the torque and the direction of couple?
A man M1 of mass 80 kg runs up a staircase in 15s. Another man M2 also of mass 80 kg runs up the same staircase in 20s. The ratio of the power developed by them will be
