Answer:
2 × 10⁶
Explanation:
Data provided in the question:
Cavity length, L = 
Oscillation frequency,
= 9.0 × 10¹⁴ Hz
Now,
we know,

here,
c is the speed of light = 3 × 10⁸ m/s
= Wavelength of mode m inside the laser cavity
m is the cavity mode number
Thus,

or
=
× 10⁻⁶
Also,

Therefore,
m ×
× 10⁻⁶ = 2 × 
or
m = 2 × 10⁶
Answer:
A. 5.4 * 10^(-4) m
B. 500V
Explanation:
A. Electric potential, V is given as:
V = kq/r
This means that radius, r is
r = kq/V
r = (9 * 10^9 * 30 * 10^(-12))/500
r = (270 * 10^(-3))/500
r = 5.4 * 10^(-4) m
B. Now the radius is doubled and the charge is doubled,
V = (9 * 10^9 * 2 * 30 * 10^(-12))/(2 * 5.4 * 10^(-4) * 2)
V = 500V
Answer:
18.5 m/s
Explanation:
On a horizontal curve, the frictional force provides the centripetal force that keeps the car in circular motion:

where
is the coefficient of static friction between the tires and the road
m is the mass of the car
g is the gravitational acceleration
v is the speed of the car
r is the radius of the curve
Re-arranging the equation,

And by substituting the data of the problem, we find the speed at which the car begins to skid:

Answer:
The weight of Earth's atmosphere exert is 
Explanation:
Given that,
Average pressure 
Radius of earth 
Pressure :
Pressure is equal to the force upon area.
We need to calculate the weight of earth's atmosphere
Using formula of pressure


Where, P = pressure
A = area
Put the value into the formula


Hence, The weight of Earth's atmosphere exert is 
Answer:
6.5 m/s^2
Explanation:
The net force acting on the yo-yo is
F_net = mg-T
ma=mg-T
now T= mg-ma
net torque acting on the yo-yo is
τ_net = Iα
I= moment of inertia (= 0.5 mr^2 )
α = angular acceleration
τ_net = 0.5mr^2(a/r)
Tr= 0.5mr^2(a/r)
(mg-ma)r=0.5mr^2(a/r)
a(1/2+1)=g
a= 2g/3
a= 2×9.8/3 = 6.5 m/s^2