Answer:
A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km. More p recisely, one light-year is equal to 9,500,000,000,000 kilometers
 
        
             
        
        
        
Answer:
The diameter is 0.000056 m
Explanation:
Lets explain the relation between the meter and the micrometer
1 Meter is equal to 1000000 (one million) micrometers
1 micrometer = 
The symbol of the meter is m
The symbol of micrometer is μm
A human hair is approximately 56 µm in diameter
We need to express this diameter in meter
To do that we divide this number by 1,000,000 or multiply it by 
→  56 µm = 0.000056 m
  56 µm = 0.000056 m
→ OR 
→  
 
→ 56 µm = 0.000056 m
<em>The diameter is 0.000056 m</em>
 
        
             
        
        
        
Answer:
BC and DE
Explanation:
In the given figure, the velocity time graph is shown. We know that the area under v-t curve gives the displacement of the particle.
Area under AB, 
Area under BC, 
Area under CD, 
Area under DE, 
Area under EF, 
So, form above calculations it is clear that, during BC and DE undergo equal displacement. Hence, the correct option is (c) "BC and DE = 4 meters".
 
        
             
        
        
        
Answer:
emf induced is 0.005445 V and direction is clockwise because we can see area is decrease and so that flux also decrease so using right hand rule direction of current here clockwise 
Explanation:
Given data
initial circumference = 165 cm
rate = 12.0 cm/s 
magnitude = 0.500 T
tome = 9 sec 
to find out 
emf induced and direction
solution
we know emf in loop is - d∅/dt    ........1
here ∅ = ( BAcosθ)
so we say angle is zero degree and magnetic filed is uniform here so that
emf = - d ( BAcos0) /dt
emf = - B dA /dt     ..............2
so  area will be
dA/dt = d(πr²) / dt
dA/dt = 2πr dr/dt
we know 2πr = c, 
r = c/2π = 165 / 2π
r  = 26.27 cm
c is circumference so from equation 2 
emf = - B 2πr dr/dt    ................3
and 
here we find rate of change of radius that is 
dr/dt = 12/2π = 1.91   cm/s
cm/s 
so when 9.0s have passed that radius of coil = 26.27 - 191 (9) 
radius = 9.08  cm
 cm
so now from equation 3 we find emf
emf = - (0.500 )  2π(9.08  )   1.91
 )   1.91  
emf = - 0.005445 
and magnitude of emf = 0.005445 V
so 
emf induced is 0.005445 V and direction is clockwise because we can see area is decrease and so that flux also decrease so using right hand rule direction of current here clockwise 
 
        
             
        
        
        
Answer:

Explanation:
By Einstein's Equation of photoelectric effect we know that

here we know that
 = energy of the photons incident on the metal
 = energy of the photons incident on the metal
 = minimum energy required to remove photons from metal
 = minimum energy required to remove photons from metal
 = kinetic energy of the electrons ejected out of the plate
 = kinetic energy of the electrons ejected out of the plate
now we know that it requires 351 nm wavelength of photons to just eject out the electrons
so we can say

here we know that

now we have

now by energy equation above when photon of 303 nm incident on the surface




