First change km/ s into m/s, then use the formula
Lambda = velocity/ frequency
Answer: A) Wavelength and frequency are inversely proportional.
Explanation:
From the wave equation;
Velocity= frequency × wavelength
If the above equation is rearranged making the frequency the subject of formula, it would give;
Frequency= velocity/ wavelength.
From the above equation we see that frequency is inversely proportional to the wavelength. This means that for every increase in wavelength there would be a decrease in frequency, and for every increase in frequency there is a reduction in wavelength.
Answer:

Explanation:
Starting from the equation:

First of all, let's multiply by t on both sides:

And then, let's divide by v on both sides:

So, finally

Answer:
(B) The wavelength that a star radiates the most energy is inversely proportional to the temperature.
Explanation:
As we know that
According to Wien's law wavelength is inverse proportional to the temperature .
λ.T = Constant.
λ.∝ 1 /T
As we know that star radiates wavelength and this wavelength is inverse proportional to the temperature of the star.
The temperature of cool star is cooler than the temperature of hot star that is cool star looks red and hot star looks blue.Cool star have low energy and hot star have high energy.
So option B is correct.
(B) The wavelength that a star radiates the most energy is inversely proportional to the temperature.
Answer:
a) The current is i = 1.2 A
b) The charge is Q = 17280 C
c) The energy is E = 43200 J
Explanation:
a) The current is given by the ohm's law wich is:
i = V/R = 3/2.5 = 1.2 A
b) Since the charge is steady we can use the following equation to find the charge amount in that time:
i = Q/t
Q = t*i
Where t is in seconds, so we have 4h * 3600 = 14400 s
Q = 1.2*14400 = 17280 C
c) The energy is the power delivered to the toy multiplied by the time:
P = 1.2*2.5 = 3 W
E = P*t = 3*14400 = 43200 J