What is the physical meaning of the 'Work Function' of a metal in the context of the photoelectric effect?
A. The electrical resistance of the metal when light shines on it.
B. The total energy of an incident photon.
C. The minimum energy required to eject an electron from the metal surface.
D. The maximum kinetic energy of an emitted electron.
Answer: Option C
Solution (By JKSSB Mock Tests)
In Einstein's photoelectric theory, electrons are bound to the metal lattice. The 'work function' (often denoted by Phi or W) is defined strictly as the absolute minimum thermodynamic work (energy) needed to overcome these binding forces and remove an electron from the surface into a vacuum. If incident photon energy (hf) is less than the work function, absolutely no emission occurs.
Explanation:
Thomas Alva Edison invented the practical incandescent light bulb in 1879. He also invented phonograph. Tesla contributed to AC system. Faraday electromagnetic induction. Bell telephone.
Explanation:
At highest point velocity is zero, but acceleration due to gravity is still g (9.8 m/s²) downward. This causes it to fall back. Acceleration constant throughout free fall.
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