Answer:
D. 160 nm
Explanation:
The energy released from n = 3 to n = 1 must be equal to the sum of energies released from n = 3 to n = 2 and from n = 2 to n = 1. Therefore,
Energy of Photon from 3 to 1 = Energy of Photon from 3 to 2 + Energy of Photon from 2 to 1

where,
λ = wavelength of photon released from 3 to 1 = ?
λ₁ = wavelength of photon released from 3 to 2 = 800 nm
λ₂ = wavelength of photon released from 2 to 1 = 200 nm
Therefore,

Therefore, the correct option is:
<u>D. 160 nm</u>
<span>The amount of heat energy needed to increase the temperature of a substance by </span>

<span> is given by:
</span>

<span>
where m is the mass of the substance, Cs is its specific heat capacity and </span>

<span> is the increase in temperature of the substance.
In this problem, we have a certain mass m of gold, with specific heat capacity </span>

<span>, to which we add Q=2825 J of energy. Its temperature increases by </span>

<span>. Therefore, if we re-arrange the previous equation, we can find the mass of the block of gold:
</span>

<span>
So, the correct answer is B.</span>
power energy potential energy
Answer:
(d) 44.8°
Explanation:
For refraction,
Using Snell's law as:
Where,
Θ₁ is the angle of incidence
Θ₂ is the angle of refraction
n₁ is the refractive index of air which is 1
n₂ is the refractive index of water which is 4/3
Given that angle of incidence = 70°
So,
<u>Angle of refraction = sin⁻¹ 0.7048 = 44.8°.</u>