Answer:
Focal length of the lens, f = - 68 mm
Explanation:
Given that,
Power of a lens, P = -14.50 D
We need to find the focal length of the lens. We know that the focal length and the power of lens has inverse relationship. Mathematically, it is given by :

f is the focal length of the lens

f = -0.068 m
or
f = -68 mm
So, the focal length of the lens is (-68 mm). Hence, this is the required solution.
Complete question:
How many x-ray photons per second are created by an x-ray tube that produces a flux of x rays having a power of 1.00 W. Assume the average energy per photon in 78.0 keV.
Answer:
The number of x-ray photons per second created by the x-ray tube is 8.01 x 10¹³ photons/sec
Explanation:
Given;
power of the flux produced, P = 1 W = 1 J/s
energy per photon, E = 78 keV
Convert the energy per photon to J
E = 78 x 10³ x 1.6 x 10⁻¹⁹ = 1.248 x 10⁻¹⁴ J / photon
let the number of photons = n
n(1.248 x 10⁻¹⁴ J / photon) = 1 J/s

Therefore, the number of x-ray photons per second created by the x-ray tube is 8.01 x 10¹³ photons/sec
Deacceleration causing reverse of speed impact on the body of the frame causing reverse of shockwave.
Answer:
0.02 s
Explanation:
Take the (+x) direction to be up.
The average velocity v during a time interval Δt is the displacement Δx divided by Δt.
v=Δx/Δt
=x_f-x_i/t_f-t_i (1)
We assume that your height is 1.6m
Solving [1]
Δt=Δx/v
= 0.02 s
Electromagnet is in form of solenoid
and the magnetic field due to solenoid is given as

here
i = current in the loop
so when we increase the current in electromagnet the magnetic field of the solenoid will increase
this will increase the strength of the electromagnet
so the answer would be
<em>INCREASE</em>