1. Frequency: 
The frequency of a light wave is given by:

where
is the speed of light
is the wavelength of the wave
In this problem, we have light with wavelength

Substituting into the equation, we find the frequency:

2. Period: 
The period of a wave is equal to the reciprocal of the frequency:

The frequency of this light wave is
(found in the previous exercise), so the period is:

Answer:60 ohms
Explanation:
R1=30 ohms
R2=15 ohms
R3=15 ohms
Let the total resistance be R
R=R1 + R2 + R3
R=30 + 15 +15
R=60
Total resistance is 60 ohms
Answer:
d)energy
Explanation:
Waves can transfer energy over distance without moving matter the entire distance. For example, an ocean wave can travel many kilometers without the water itself moving many kilometers. The water moves up and down—a motion known as a disturbance. It is the disturbance that travels in a wave, transferring energy.
Answer:
T1 = 130N, T2 = 370N
Explanation:
In order for the system to be at rest, the sum of all forces must be zero and the torque around a point on the beam must be zero.
1. forces:
Let tension in rope 1 be T1 and in rope 2 be T2:
ma = T1 + T2 - 100N - 400N = 0
(1) T1 + T2 = 500N
2. torque around the center point of the beam:
τ = r x F = 5*T1 + 3*400N - 5*T2 = 0
(2) T1 - T2 = -240N
Solving both equations:
T1 = 130N
T2 = 370N
Answer:

Explanation:
The period of a simple pendulum is given by:

where
L is the length of the pendulum
g is the acceleration of gravity
From this equation we can write

Taking the square of this equation, we get:

So we see that
is proportional to L and inversely proportional to g. So, we can write:

So the only correct option is
