Question

two bulbs a and b emit red light and yellow light at 8000 angstorms and 4000 angstroms respectively. The no of photons emitted by both the bulbs per second is the same. If the red bulb is labelled 100 watts find the wattage of the yellow bulb​

Answer 1

Answer:

133.33 W

(Assuming the number of photons emitted per second are the same for both the bulbs)

Explanation:

Wattage of red bulb = 100W

Now, using Einstein's Equation,

Energy (E) = hc / λ

where h = planks constant and c = speed of light/electromagnetic waves

We can say, Energy ∝ 1/ λ

Therefore, wavelength of red light is 8000 angstrom,

while of yellow light is 6000 angstrom,

Therefore,

6000/8000 = 100/x   →   (inverse proportion)

x = wattage of yellow light bulb = 133.33 W (assuming no. of photons emitted per second are the same for both the bulbs)

Answer 2

Answer:

Explanation:

6000/8000 = 100/x   →   (inverse proportion)

x = wattage of yellow light bulb = 133.33 W (assuming no. of photons emitted per second are the same for both the bulbs)