Answer:
This is because The energies of atoms are quantized.
Electrons are allowed "in between" quantized energy levels, and, thus, only specific lines are observed
Answer: car 1 is going how fast
Explanation: no need to answer without speed I won't know distance.
I'm in physics, but I think the answer is 22. The angle of reflection is reflecting whatever the angle was so, in this case, it must be 22
Answer:B)439.21 Hz
Explanation:
Given
velocity of train 
frequency of train 
speed of sound 
frequency from Doppler effect can be calculated by
Answer:
c = e > b = d > a
Explanation:
Given vectors are all unit vectors, therefore they have a magnitude of 1
<h3>Let a, b be two vectors and magnitude of cross product of these two vectors is (magnitude of a) × (magnitude of b) × (sine of angle between these two vectors)</h3>
As all are unit vectors their magnitude is 1 and therefore in this case the cross product between any two vectors depends on the sine of angle between those two vectors
In option a as both the vectors are same, the angle between them will be zero and sin0° will also be 0
In option b angle between those two vectors is 135° and sin135° is 1 ÷ √2
In option c angle between those two vectors is 90° and sin90° is 1
In option d angle between those two vectors is 45° and sin45° is 1 ÷ √2
In option e angle between those two vectors is 90° and sin90° is 1
So by comparison of magnitudes of cross products in each option, the order will be c = e > b = d > a
