Concave Mirror is a mirror with a curved reflecting surface that is bulging inward. This is the opposite of Convex Mirror which has a bulging outward surface. Concave mirrors are also called converging mirrors. The concave mirror reflected the light inward to a single focal point. These are usually used in reflecting telescopes.
Answer:
f = 7.97 x 10⁶ Hz = 7.97 MHz
Explanation:
The speed of a wave is given by the following formula:

where,
v = speed of the ultrasound wave through human tissue = 1540 m/s
f = frequency of ultrasound wave required = ?
λ = wavelength of ultrasound waves = smallest detail required = 0.193 mm
λ = 0.193 mm = 1.93 x 10⁻⁴ m
Therefore,
<u>f = 7.97 x 10⁶ Hz = 7.97 MHz</u>
Explanation:
Given that,
Average power of sun 
We need to calculate the intensity of light at Earth's position
Using formula of intensity

Where, I = intensity
P = power
Put the value into the formula


So, The intensity is 1347.616 W/m².
(A). We need to calculate the pressure on a solar sail due to the light of the sun if it's fully reflective
Using formula for fully reflective

Put the value into the formula


(B). We need to calculate the pressure on a solar sail due to the light of the sun if it's fully reflective
Using formula for fully absorptive



Hence, This is the required solution.
The temperature at which the sample of liquid turns to gas at 135 °C is termed as boiling point.
Answer: Option A
<u>Explanation:
</u>
The observation of conversion of liquid to gas indicates that there is occurrence of change in the state of matter. The inter-conversion from one state to another can be done by either varying the temperature or by varying the pressure.
In this case, the liquid on heating gets converted to gaseous state after attaining a particular temperature say 135 °C. So, this process of conversion from liquid to gaseous state on heating is termed as boiling.
The temperature at which a liquid converts to gas is termed as the boiling point of that liquid.