A) 4.7 cm
The formula for the angular spread of the nth-maximum from the central bright fringe for a diffraction from two slits is

where
n is the order of the maximum
is the wavelength
is the distance between the slits
In this problem,
n = 5


So we find

And given the distance of the screen from the slits,

The distance of the 5th bright fringe from the central bright fringe will be given by

B) 8.1 cm
The formula to find the nth-minimum (dark fringe) in a diffraction pattern from double slit is a bit differente from the previous one:

To find the angle corresponding to the 8th dark fringe, we substitute n=8:

And the distance of the 8th dark fringe from the central bright fringe will be given by

Answer:
B) Periodic Motion
Explanation:
When a pendulum is friction-less, i.e there are no damping forces acting on it, its motion will be periodic, i.e it will bob up and down going from potential energy to kinetic energy and back. Thus, the motion of the pendulum can be best described by the term "period motion", hence choice B.
If however, forces do act on the pendulum, and if they acts as to damp the pendulum, it will oscillate less and less as time goes by, and eventually come to a stop (in the real world this damping force is usually air resistance ). And if the force acts in such a way that it increases the oscillations, the pendulum will swing higher and higher, and the system will go haywire! :)
I think that GMOs, also known as genetically modified crops or organisms, can be used in good and bad ways. They can provide crops to survive longer, and produce a bigger portion. However, on the other side of that, it is claimed that it creates a large amount of greenhouse gas emissions, which can turn into climate change.
A)
2revs in 0.08s
so in 1s thats 25revs
therefore thats <u>50π radians</u> in one second
b)
well, ω=2π/T
therefore ω=50π = 157.079rads^-1
and v=rω where r is in meters;
v=0.3x157.079
<u>v=47.123ms^-1</u>
c)
f=1/T
f=1/period for one rotation
1 rotation = 0.08/2 = 0.04
f=1/0.04
<u>f=25Hz</u>