Help please number 8 an 9
1 answer:
8) The reason is that MRIs use radio-waves, which are electromagnetic waves with lower frequency, and so lower energy, than X-rays.
In fact, typical frequencies for radio waves are
, while X-rays have typical frequencies of 
. Since the energy of a wave is given by
where h is the Planck constant and f the frequency, we see that the lower the frequency, the lower the energy. Therefore, radiowaves have less energy than X-rays, so they are less ionising and less dangerous than X-rays.
9) The false statement is:
a) gamma-rays are low-frequency waves.
It's actually the opposite, in fact: gamma rays are the electromagnetic waves with higher frequencies (above
).
In fact, typical frequencies for radio waves are
where h is the Planck constant and f the frequency, we see that the lower the frequency, the lower the energy. Therefore, radiowaves have less energy than X-rays, so they are less ionising and less dangerous than X-rays.
9) The false statement is:
a) gamma-rays are low-frequency waves.
It's actually the opposite, in fact: gamma rays are the electromagnetic waves with higher frequencies (above
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Answer:
- F = G Newtons
Explanation:
Given:
- Mass of 1st body =
- Mass of 2nd body =
To Find:
- Magnitude of gravitational force
Solution:
Here, we have a formula
<u>Substituting the values</u>
Know More:
The applied formula for the above solution is
where,
- F
= Gravitational force
- G = Gravitational constant
- M
= mass of 1st body
- M
= mass of 2nd body
- r = distance between two bodies
Answer:
a
The time it would take the beef to reach a temperature of 0⁰C is t= 662 sec = 11.93 min
b)
The time it would take to heat the beef to uniform temperature of 80⁰C is
t = 365 sec =5.93 min
c
Efficient absorption of Microwave power is in regions of liquid water . Hence if the food or the microwave irradiation is not uniform, the power will be absorbed non-uniformly, resulting in a non-uniform temperature rise. Defrost region will absorb more energy per unit volume than frozen region.if food is of low thermal conductivity, there will be insufficient time for heat conduction to make the temperature more uniform.Use of low power allows more time for conduction to occur.
Explanation:
The explanation is shown on the first second and third uploaded image
