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:

Explanation:
Pressure at the bottom of the building and at the top of the building must be related as



now we will have




now we have


Answer:
857.5 m
2.8583×10⁻⁶ seconds
Explanation:
Time taken by the sound of the thunder to reach the student = 2.5 s
Speed of sound in air is 343 m/s
Speed of light is 3×10⁸ m/s
Distance travelled by the sound = Time taken by the sound × Speed of sound in air
⇒Distance travelled by the sound = 2.5×343 = 857.5 m
⇒Distance travelled by the sound = 857.5 m
Time taken by light = Distance the light travelled / Speed of light

Time taken by light = 2.8583×10⁻⁶ seconds
The displacement vector (SI units) is
![\vec{r} =At\hat{i}+A[t^{3}-6t^{2}]\hat{j}](https://tex.z-dn.net/?f=%5Cvec%7Br%7D%20%3DAt%5Chat%7Bi%7D%2BA%5Bt%5E%7B3%7D-6t%5E%7B2%7D%5D%5Chat%7Bj%7D)
The speed is a scalar quantity. Its magnitude is

Answer: At√(t⁴ - 12t³ + 36t² + 1)
At the end of the laps, the runner's displacement is zero.