The maximum displacement of a particle from mean position in SHM is called MCQ with Answer and Explanation

Explanation:
Beat frequency is the absolute difference between two frequencies. Given 4 beats with 256 Hz, the unknown fork is either 256+4=260 Hz or 256-4=252 Hz. Adding wax increases mass, which strictly lowers the frequency of a fork. If it was 252 Hz, lowering it would increase the gap from 256, increasing beats. If it was 260 Hz, lowering it brings it closer to 256, decreasing beats to 2. Thus, it was originally 260 Hz.

Explanation:
According to Einstein's photoelectric equation, the kinetic energy of emitted electrons depends exclusively on the frequency of the incident light and the metal's work function. Intensity represents the number of photons striking the surface per second. More photons mean more collisions with electrons, leading strictly to an increase in the number of emitted photoelectrons (photoelectric current), not their energy.

Explanation:
LEDs are highly efficient, converting ~80-90% of electrical energy into light, rest heat. Incandescent bulbs ~10% efficient. LED long life, low power. Blue LED Nobel prize 2014.