Answer:
D. Light only
Explanation:
This is because photoelectric effect is a phenomenon in which electrically charged particles are emitted from a material when light is incident on it.
The light generates the energy which causes the material to emit electrons.
These electrons are only emitted at certain values of light energy, this thus shows that the light has to be quantized since electrons are not emitted over a range of values of light energy.
Thus, to fully describe the photoelectric effect, only light needs to be quantized.
This looks like the photo electric effect ... classical physics reckoned that if you shone an intense enough light beam on a metal you could get electrons ejected from the metal (maybe in analogy to thermionic emission - heat). It sort of "forgot" about the frequency and photon/particle nature of light.
Enter the "photo electric" effect experiment, Einstein's explanation, and the Nobel committee having an excuse to award E a Nobel prize, even though said prize was probably more for relativity.
<h2>
Answer:</h2>
(c) 5m/s²
<h2>
Explanation:</h2>
Total acceleration (a) of a particle in a circular motion is the vector sum of the radial or centripetal acceleration (
) of the particle and the tangential acceleration (
) of the particle and its magnitude can be calculated as follows;
a =
---------------------(i)
<em>But;</em>
=
------------------------------(ii)
Where;
v = instantaneous velocity
r = radius of the circular path of motion
<em>From the question;</em>
v = 30m/s
r = 300m
(i) First let's calculate the centripetal acceleration by substituting the values above into equation (ii) as follows;
= 
= 
= 3m/s²
(ii) From the question, the velocity of the particle is increasing at a constant rate of 4m/s² and that is the tangential acceleration
, of the particle. i.e;
= 4m/s²
(iii) Now substitute the values of
and
into equation (i) as follows;
a = 
a = 
a = 
a = 5m/s²
Therefore, the magnitude of its total acceleration a, is 5m/s²
Answer:
Charge, 
Explanation:
It is given that,
Electric field strength, E = 180000 N/C
Distance from a small object, r = 2.8 cm = 0.028 m
Electric field at a point is given by :

Q is the charge on an object



So, the charge on the object is
. Hence, this is the required solution.
Answer:
r = 4.21 10⁷ m
Explanation:
Kepler's third law It is an application of Newton's second law where the forces of the gravitational force, obtaining
T² = (
) r³ (1)
in this case the period of the season is
T₁ = 93 min (60 s / 1 min) = 5580 s
r₁ = 410 + 6370 = 6780 km
r₁ = 6.780 10⁶ m
for the satellite
T₂ = 24 h (3600 s / 1h) = 86 400 s
if we substitute in equation 1
T² = K r³
K = T₁²/r₁³
K =
K = 9.99 10⁻¹⁴ s² / m³
we can replace the satellite values
r³ = T² / K
r³ = 86400² / 9.99 10⁻¹⁴
r = ∛(7.4724 10²²)
r = 4.21 10⁷ m
this distance is from the center of the earth