Answer:
Boiling point of water is 100 deg C. It takes about 540 cal to change 1 g of water at the boiling point to 1 g of steam at 100 deg C.
Answer:
Answer is B.
Because the wavelength of infrared is shorter than microwave radiation
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.
Answer:

Explanation:
From the conservation of mechanical energy




Solve to velocity v2



