Answer:
Explanation:
Given
speed of Electron 
final speed of Electron 
distance traveled 
using equation of motion

where v=Final velocity
u=initial velocity
a=acceleration
s=displacement


acceleration is given by 
where q=charge of electron
m=mass of electron
E=electric Field strength

Answer:
The lenses with different focal length are four.
Explanation:
Given that,
Radius of curvature R₁= 4
Radius of curvature R₂ = 8
We know ,
Refractive index of glass = 1.6
When, R₁= 4, R₂ = 8
We need to calculate the focal length of the lens
Using formula of focal length

Put the value into the formula



When , R₁= -4, R₂ = 8
Put the value into the formula



When , R₁= 4, R₂ = -8
Put the value into the formula



When , R₁= -4, R₂ = -8
Put the value into the formula



Hence, The lenses with different focal length are four.
Answer:

Explanation:
a) Fundamental frequency
A harmonic is an integral multiple of the fundamental frequency.


b) Wave speed
(i) Calculate the wavelength
In a fundamental vibration, the length of the string is half the wavelength.

(b) Calculate the speed
s



Question:
1) The universe is cooling which, according to the Big Bang Theory, is expected to happen as the cosmos accumulates.
2) The universe is warming which, according to the Big Bang Theory, is expected to happen as the cosmos disperses.
3) The universe is cooling which, according to the Big Bang Theory, is expected to happen as the cosmos disperses.
4) The universe is warming which, according to the Big Bang Theory, is expected to happen as the cosmos accumulates.
Answer:
The correct option is;
3) The Universe is cooling which, according to the Big Bang Theory, is expected to happen as the cosmos disperses
Explanation:
With the temperature measurement carried out using the CSIRO radio telescope, Astronomers have been able to determine a temperature difference in the universe from 5.08 Kelvin 7.2 billion light years away to 2.73 Kelvin in the Universe today, which is in support of the Big Bang theory that as the Universe expanded from a state of extreme temperature that cools down as the Universe expands or the cosmos disperses.
J.J. Thompson is the scientist who recieved credit for discovering them.