If i was feeling harsh today, I'd say the answer to your question is impossible to obtain due to the fact that photons do not emit radiation, photons ARE the radiation emitted. Though for the sake of it, here is the method...
<u>The simple method:
</u>
E=hf
therefore f=e/h
f=(3.611x10^-15) / 6.63x10^-34)
Answer: 5.45x10^18
As we know that range of the projectile motion is given by

here we know that range will be same for two different angles
so here we can say the two angle must be complementary angles
so the two angles must be

so it is given that one of the projection angle is 75 degree
so other angle for same range must be 90 - 75 = 15 degree
so other projection angle must be 15 degree
Answer:
20.60 kV
Explanation:
Capacitance of parallel plates without dielectric between them is:

with d the distance between the plates, A the area of the plates and ε₀ the constant
, so :

But the dielectric constant is defined as:

With C the effective capacitance (with the dielectric) and Co the original capacitance (without the dielectric). So, the new capacitance is:

But capacitance is related with voltage by:

with Q the charge and V the voltage, using the new capacitance and solving for V:

