Answer:
Explanation:
given,
refractive index of lens, n = 1.70
Radius of curvature of front surface. R₁ = 20 cm
Radius of curvature of the back surface, R₂ = 30 cm
focal length= ?
R₁ = +20 cm
R₂ = -30 cm
n = 1.70
the focal length of the lens is equal to 17.15 cm
Answer:
a) 46.5º b) 64.4º
Explanation:
To solve this problem we will use the laws of geometric optics
a) For this part we will use the law of reflection that states that the reflected and incident angle are equal
θ = 43.5º
This angle measured from the surface is
θ_r = 90 -43.5
θ_s = 46.5º
b) In this part the law of refraction must be used
n₁ sin θ₁ = n₂. Sin θ₂
sin θ₂ = n₁ / n₂ sin θ₁
The index of air refraction is n₁ = 1
The angle is this equation is measured between the vertical line called normal, if the angles are measured with respect to the surface
θ_s = 90 - θ
θ_s = 90- 43.5
θ_s = 46.5º
sin θ₂ = 1 / 1.68 sin 46.5
sin θ₂ = 0.4318
θ₂ = 25.6º
The angle with respect to the surface is
θ₂_s = 90 - 25.6
θ₂_s = 64.4º
measured in the fourth quadrant
Speed of sound in cold air < Speed of sound in Warm air < Speed of sound in hot molten lead < Speed of sound in water
Explanation:
Step 1:
Speed of sound in water varies from 1450 to 1498 meters per second
Speed of sound in Hot Molten lead is approximately 1210 meters per second
Speed of sound in warm air is approximately 338.89 meters per second
Speed of sound in cold air is approximately 293.33 meters per second
Step 2:
In warm air sound travels faster than that of sound travelling nature in cold air.
∴ Speed of sound in cold air < Speed of sound in Warm air < Speed of sound in hot molten lead < Speed of sound in water
Speed of sound in cold air the slowest while Speed of sound in water is the fastest mean.
Answer:
v=77.62 m/s
Explanation:
Given that
h= - 300 m
speed of the bird ,u= 5 m/s
Lets take Speed of the berry when it hit the ground = v m/s
we know that ,if object is moving upward
v² = u² - 2 g h
u=Initial speed
v=Final speed
h=Height
Now by putting the values
v² = u² - 2 g h
v² = 5² - 2 x 10 x (-300) ( take g = 10 m/s²)
v² =25 + 20 x 300
v² ==25 + 6000
v² =6025
v=77.62 m/s
Therefore the final speed of the berry will be 77.62 m/s.
Answer:
You would have to give better explanation on subject.
Explanation:
