We know that the intensity of light decreases as the square of the distance
from the source.
Lamp-1 is twice (2x) as far from the detector as Lamp-2 is.
If they appear equal to the detector, then Lamp-1 must be (2)² = 4 times
as bright as Lamp-2.
4 x 15 candelas = 60 candelas
Question #15).
A). is true, but has nothing to do with particle behavior
B). Diffraction is a purely wave thing, so it doesn't help.
C). is true, but doesn't say anything about particle behavior
D). is true, but isn't an indication of particle behavior.
Looks to me like NONE of the choices is any help
to suggest particle behavior.
0.017s
Explanation:
Given parameter
Distance = 5000km = 5 x 10⁶m
Unknown:
time taken = ?
Solution:
We use the normal speed equation to solve this problem as we take the speed of the wave to be 3 x 10⁸m/s.
Speed = 
Inputting the parameters:
Time taken = 
Time taken =
= 0.017s
Learn more:
Earthquake brainly.com/question/11292835
#learnwithBrainly
Electrical energy is used to run the fan
Here as per given condition 750 J of electrical energy is used to run the fan which is converted into Kinetic energy as 400 J
So here we can see that 350 J of energy is lost against many other type of frictional and resistive loses.
So here we can say that out of 750 J of energy only 400 J is used to run the fan and rest amount of energy is lost against friction.
also we can say that efficiency of this fan will be



Answer:
12 meters per second (12 m/s)
why?
Because if you divide 10 seconds by 10 and 120 by 10, you will get 12 meters in 1 second.