Answer:
c. 307 nm
Explanation:
angular position of first dark fringe = λ / d , λ is wavelength and d is width of slit .
(40 x π ) / 180 = 410 / d
angular position of second dark fringe = 2 x λ / d , λ is wavelength and d is width of slit .
(60 x π ) / 180 = 2 x λ / d
Dividing these equations
60 / 40 = 2 x λ / 410
λ = 307.5 nm.
Answer:

Explanation:
Given that,
The instantaneous current in the circuit is giveen by :

We need to find the rms value of the current.
The general equation of current is given by :

It means, 
We know that,

So, the rms value of current is 2.12 A.
<em>"A concave lens is thinner at the center than it is at the edges."</em>
If this isn't on the list of choices, that's tough. We can't help you choose the best one if we don't know what any of them is.
Answer:
1. the electromagnetic wave.
Explanation:
Mathematically,
wavelength = velocity ÷ frequency
A mechanical wave is a wave that is not capable of transmitting its energy through a vacuum. Mechanical waves require a medium in order to transport their energy from one location to another. A sound wave is an example of a mechanical wave. Sound waves are incapable of traveling through a vacuum.
Electromagnetic waves of different frequency are called by different names since they have different sources and effects on matter, increasing frequency decreases wavelength.
Sound waves (which obviously travel at the speed of sound) are much slower than electromagnetic waves (which travel at the speed of light.)
Electromagnetic waves are much faster than sound waves and If the Velocity of the wave increases and the frequency is constant, the wavelength also increases.
Answer:
1. Luminosity
2.Apparent brightness
Explanation:
There are two factors on which brightness of star appear to be in the sky
The two factors are
1. Luminosity
2.Apparent brightness
1.Luminosity :It is defined as the total energy emitted by the object in a given time.Luminosity vary with the distance of observer from the star.Luminosity is a intrinsic property which depends on the fundamental chemical composition and structure of the material.Luminosity is depends on the size of star.Lager the star luminosity will be more.
2.Apparent brightness: It is defined as how bright a star appears from an observer on the earth and the amount of starlight reaching the earth.if the distance is large then the brightness decreases.When the distance of star from us small then the brightness of star increases.Distance is inversely proportional to brightness of the star.