Answer:
162500000.
Explanation:
Given that
Diameter of the wire , d= 1.8 mm
The length of the wire ,L = 15 cm
Current ,I = 260 m A
The charge on the electron ,e= 1.6 x 10⁻¹⁹ C
We know that Current I is given as

I=Current
q=Charge
t=time
q= I t
q= 260 m t
The total number of electron = n
q= n e

n=162500000 t

The number of electron passe per second will be 162500000.
Answer:

Explanation:
As we know that when electron moved in electric field then work done by electric field must be equal to the change in kinetic energy of the electron
So here we have to find the work done by electric field on moving electron
So we have



now the distance moved by the electron is given as

so we have



now we have to convert it into keV units
so we have


We have to convert Gm/s to m/s.
As 
Therefore the speed of light in vacuum,

Thus, the speed of light in m/s is 
Answer:
A. τ = 358 N.m
B. m = 73kg
C. V = 209.5 m/s
Explanation:
Let's first convert angular speed to rad/s:
ω = 4000 rev/min * 2π / 60 = 419 rad/s
Since Power is P = τ * ω,
τ = P / ω = 358 N.m
For part B: On the hanging weight:
T - m*g = 0
T = m*g
On the drum:
τ = T*R Replacing the expression for Tension of the rope:
τ = m*g*R
Solving for m:
m = 73 kg
For part C:
V = ω * R = 209.5 m/s
(a) Amplitude=1.5 m
Amplitude is the maximum distance from the mean (zero disturbance) position.Here amplitude= 1.5 m
(b) wavelength= 2 m
Wavelength is the length of one complete wave or distance traveled by a wave in a time equal to Time Period. Here wavelength= 2 m
(c) Frequency=7.5 Hz
using equation for wave velocity V= f λ
15= f (2)
f=7.5 Hz
so frequency=7.5 Hz
(d) Time period= 0.133 s
Time period= T= 1/f
T= 1/7.5
T=0.133 s
so time period=0.133 s