Answer:
2 m = E / c^2 where m is mass of electron
E = h v where v is the frequency ( nu) of the incident photon
E = h c / y where y is the incident wavelength (lambda)
2 m = h / (c y)
y = h / (2 m c) wavelength required
y = 6.62 * 10E-34 / (2 * 9.1 * 10E-31 * 3 * 10E8) m
y = 3.31 / 27.3 E-11 m
y = 1.21 E -12 m = .0121 Angstrom units
Answer:
The distance is 
Explanation:
From the question we are told that
The coefficient of static friction is 
The initial speed of the train is 
For the crate not to slide the friction force must be equal to the force acting on the train i.e

The negative sign shows that the two forces are acting in opposite direction
=> 
=> 
=> 
=> 
From equation of motion

Here v = 0 m/s since it came to a stop
=> 
=> 
=> 
Answer:
the answer is B
Melting point, temperature at which the solid and liquid forms of a pure substance can exist in equilibrium. As heat is applied to a solid, its temperature will increase until the melting point is reached. More heat then will convert the solid into a liquid with no temperature change.
1) Refraction
2)Reflection
3)Concave
4)Convex
I took the test and got this right so you can believe me :)
Hope this helps