Answer
B. X
A plate of glass or metal ruled with very close parallel lines, producing a spectrum by diffraction and interference of light.
diffraction grating is an optical component that splits and diffracts light into several beams travelling in different directions. The light emerges with its colours separated.
The answer is c. it requires no works
Take the stone's position at ground level to be the origin, and the downward direction to be negative. Then its position in the air 
at time 
is given by
Let 
be the depth of the well. The stone hits the bottom of the well after 5.00 s, so that
Answer:
induced emf = 28.65 mV
Explanation:
given data
diameter = 7.3 cm
magnetic field = 0.61
time period = 0.13 s
to find out
magnitude of the induced emf
solution
we know radius is diameter / 2
radius = 7.3 / 2
radius = 3.65 m
so induced emf is dπ/dt = Adb/dt
induced emf = A × ΔB / Δt
induced emf = πr² × ΔB / Δt
induced emf = π (0..65)² × ( 0.61 - (-0.28)) / 0.13
induced emf = 0.0286538 V
so induced emf = 28.65 mV
