Heat used by electric heater :
Q = m • c • ∆T
Q = (75 kg)(4200 J/kg°C)(43°C - 15°C)
Q = 8.82 × 10⁶ J
Cost of electrical energy :
Cost = (8.82 × 10⁶ J)/(3.6 × 10⁶ J) • ($ 0.15)
Cost = $ 0.3675
I think it's A) Sunspots. I hope this helps:)
Answer:
Light of a shorter wavelength should be used.
Explanation:
This is studied in the phenomenon called photoelectric effect, in which light is able to release electrons from a metal, said electrons are called photoelectrons .
The experiments that have been carried out show that <u>increasing or decreasing the intensity of the light will not cause the photoelectrons to be emitted</u>, what will cause the photoelectrons to be emitted is to increase the frequency of the incident light.
And a higher frequency corresponds to a shorter wavelength according to the equation:

(where
is frequency,
the speed of light, and
the wavelength)
So the answer is that the wavelength of the light must be shortened to cause the emission of electrones.
1,000 W = 1 kW
100 W = 0.1 kW
(0.1 kW) x (6 h) = 0.6 kWh <=== energy
(0.6 kWh) x (£0.1359/kWh) = £0.0815 <=== cost of it
Explanation:
To be accurate, it must be able to make measurements that are close to the actual value.