Answer:
Explanation:
Intensity of light is inversely proportional to distance from source
I ∝ 1 /r² where I is intensity and r is distance from source . If I₁ and I₂ be intensity at distance r₁ and r₂ .
I₁ /I₂ = r₂² /r₁²
If r₂ = 4r₁ ( given )
I₁ / I₂ = (4r₁ )² / r₁²
= 16 r₁² / r₁²
I₁ / I₂ = 16
I₂ = I₁ / 16
So intensity will become 16 times less bright .
"16 times " is the answer .
Answer: Electromagnets can be turned on and off by controlling the current
Explanation:
Answer:

Explanation:
The gravitational potential at a point on the Earth surface is given by:

where
G=6.67×10^-11Nm^2kg^-2 is the gravitational constant
M=5.98×10^24kg is the Earth's mass
R=6.38×10^6 m is the Earth's radius
Substituting the numbers into the equation, we find
