Answer:
The apparent depth of (a) the fish is 5.3 cm and (b) the image of the fish is 24.8 cm.
Explanation:
According to the following equation:

where <em>nw</em> and <em>na</em> is the refractive indices of water (1.33) and air (1.00) respectively; <em>s</em> is the depth of the fish below the surface of the water; s' is the apparent depth of the fish from normal incidence and Rc is the radius of curvature of the mirror at the bottom of the tank.
Note that the bottom of the tank is assumed to be a flat mirror, therefore the radius of curvature is very large (R⇒∞).
Therefore, the above equation can be expressed as:

Now we can solve for the apparent depth of the fish.
(a)
(Make s' subject of the formula from the above equation)

∴ 
(b) The motionless fish floats 13 cm above the mirror, therefore the image of the fish will be situated at 13 + 20 =33 cm away from the real fish.
Therefore, s = 33 cm



NB: Here, it is assumed that the water is pure, as impurities may alter the refractive index of water.
Answer:
Explanation:
mass of electron in amu = .000549
mass of electron = mass of proton
total mass of electron and proton = 2 x1.098 x 10⁻³ = 2.196 x 10⁻³ amu
1 amu = 931 x 10⁶ eV
2.196 X 10⁻³ amu = 2.196 x 931 x 10³ eV
= 2.044 X 10⁶ eV.
= 2044 X 10³ ev
So minimum energy required = 2044 x 10³ eV.
Wavelength of photon required = 12375/2044 x 10³ A
= 6.054 X 10⁻³A. =6.054 X 10⁻¹³ m
frequency of photon = 3 x 10⁸/6.054x 10⁻¹³
= .4955 x 10¹⁶Hz.
= 4.955 x 10¹⁵ Hz
For all elastic collisions we have



also by momentum conservation we will have

since two cars are identical so we know that


now by solving two equations we will have


so the correct answer must be
It attains the same speed as the first car.
Its a proces of combustion "burning"humans produce carbon dioxide,rocks<plants whatever is burning energy