The second one is correct not sure about the first one sorry
Answer:
The angle of incidence when the reflected ray is perpendicular to the incident ray = 45°
Explanation:
According to Snell's Law,
n₁ sin θ₁ = n₂ sin θ₂
When the angle between the incident ray and reflected ray is 90°, the angle of incidence is θ₁ and the angle of reflection, θ₂ = 90° - θ₁ and the index of refraction in the Snell's Law for both media would be the same, n₁ = n₂ = n
n sin θ₁ = n sin (90° - θ₁)
Note that from trigonometric relations,
Sin (90° - θ₁) = cos θ₁
n sin θ₁ = n cos θ₁
(sin θ₁)/(cos θ₁) = 1
tan θ₁ = 1
θ₁ = arctan 1 = 45°
Hope this Helps!!!
because as the distance increases the gravitational force decreases so the weight of a body decreases
An energy bar contains of 20grams of carbohydrates and 1gram
is equal to 17 KJ. If the energy bar was his only fuel the total energy
available is equal to (17,000 x 20) = 340,000j. Estimate KJ per hour is equal
to 1539KJ, it has Time equal to (340,000/1539,000) is equal to 0.2209 hour and
his Distance is equal to (5,000 x .2209) = 1.1045km.