Answer:
28.23 years
Explanation:
I = 1100 A
L = 230 km = 230, 000 m
diameter = 2 cm
radius, r = 1 cm = 0.01 m
Area, A = 3.14 x 0.01 x 0.01 = 3.14 x 10^-4 m^2
n = 8.5 x 10^28 per cubic metre
Use the relation
I = n e A vd
vd = I / n e A
vd = 1100 / (8.5 x 10^28 x 1.6 x 10^-19 x 3.14 x 10^-4)
vd = 2.58 x 10^-4 m/s
Let time taken is t.
Distance = velocity x time
t = distance / velocity = L / vd
t = 230000 / (2.58 x 10^-4) = 8.91 x 10^8 second
t = 28.23 years
The work done by the elephant to lift one log is the force multiplied by the height at which the log has been lifted:

And so, the total work done to lift the 7 logs is 7 times the work done to lift each log:
7. PE=0.5×700n/m×0.9m^2
0.9^2=0.81m
0.5×700×0.81= 283.5J
8. 2000=0.5×(x)×1.5m^2
1.5^2= 0.25
0.25×0.5=0.125
2000=0.125 (x)
2000/0.125=x
x=16000 n/m
9. 4000=0.5 (375 n/m)×(x)^2
0.5×187.5 (x)
4000/187.5=21.3333333333
Answer:
Explanation:
λ = wave length = 632 x 10⁻⁹
slit width a = 2 x 10⁻³ m
angular separation of central maxima
= 2 x λ /a
= 2 x 632 x 10⁻⁹ / 2 x 10⁻³
= 632 x 10⁻⁶ rad
width in m of light spot.
= 632 x 10⁻⁶ x 376000 km
= 237.632 km
Answer:
Explanation:
Let the thickness of the film is t and the refractive index of the material of film is n.
When light travels through a sheet of thickness t, the optical path traveled is nt.
When the path of one of slit is covered by a sheet of thickness t, the optical path becomes
x = ( n - 1) t
As the one fringe is shift, so the optical path changed by one wavelength.
i.e., x = λ
So, λ = ( n - 1) t
