It could be A :) not sure tho
Answer:

Explanation:
n = Order = 1
c = Speed of light = 
f = Frequency = 
= Angle = 
Lattice spacing is given by

The lattice spacing of the crystal is 
Answer:
increase
Explanation:
According to Einstein's photoelectric equation; the energy of a photon striking a metal surface is related to the kinetic energy of the ejected photoelectron by the formula;
KE= hf - hfo
Where h is the planks constant, f and fo refer to the frequency of incident photon and the threshold frequency respectively.
Hence, we can clearly see from the foregoing that the kinetic energy of the ejected photoelectron is proportional to the frequency of the incident photon.
Hence, if the frequency of the incident photon is increased, the kinetic energy of the ejected photoelectron increases also.
Answer:
Consciousness is a psychological construct because it is believed to exist, but we are unable to physically measure it, so descriptions are 'constructed' to explain it. ... The more aware we are of our thoughts, feelings, perceptions and surroundings, the higher the level of consciousness.
Answer:
Less
Explanation:
because static friction is more than rolling friction