Asingle slit is illuminated by light of wavelengths λa and λb, chosen so that the first diffraction minimum of the λa component coincides with the second minimum of the λb component. (a) if λb = 370 nm, what is λa? for what order number mb (if any) does a minimum of the λb component coincide with the minimum of the λa component in the order number (b) ma = 4 and (c) ma = 5?

Explanation:

First minimum of λa will be formed at 1 x λa D/d distance from the centre where D is distance of screen and d is width of slit.

As per given statement

λa D/d = 2 x λb D/d

λa  = 2 x λb

= 2 x 370 nm

= 740 nm

Let ma  th order of λa component coincides with mb the order of λb component

ma λa D/d = mb λb D/d

ma / mb = λb / λa

ma / mb = 1/ 2

mb = 2 ma

if ma = 4

mb = 8

if ma = 5

mb = 10

change tension

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.