Answer:
The lenses with different focal length are four.
Explanation:
Given that,
Radius of curvature R₁= 4
Radius of curvature R₂ = 8
We know ,
Refractive index of glass = 1.6
When, R₁= 4, R₂ = 8
We need to calculate the focal length of the lens
Using formula of focal length

Put the value into the formula



When , R₁= -4, R₂ = 8
Put the value into the formula



When , R₁= 4, R₂ = -8
Put the value into the formula



When , R₁= -4, R₂ = -8
Put the value into the formula



Hence, The lenses with different focal length are four.
<u>Answer:</u>
0.24 m
<u>Explanation:</u>
Given:
Wave velocity ( v ) = 360 m / sec
Frequency ( f ) = 1500 Hz
We have to calculate wavelength ( λ ):
We know:
v = λ / t [ f = 1 / t ]
v = λ f
= > λ = v / f
Putting values here we get:
= > λ = 360 / 1500 m
= > λ = 36 / 150 m
= > λ = 0.24 m
Hence, wavelength of sound is 0.24 m.
Answer:
B
Explanation:
it's converts electrical energy to mechanical energy.
Все написано в скобках правильно
Add the KE increase and the work done against friction.
The final velocity is twice the average, or 3.0 m/s
The final KE is (1/2)*25*3^2 = 112.5 J
The friction work done is 6*3.8 = 22.8 J
hope this is correct