C. Energy can change forms
Answer:
The time is 2.8 ms.
Explanation:
Given that,
Capacitor = 0.12 μF
Resistance = 10 kohm
Voltage = 12 V
Charge Q = 0.9 Q₀
We need to calculate the time constant
Using formula of time constant

Put the value into the formula


We need to calculate the time
Using formula of time

Put the value into the formula




Hence, The time is 2.8 ms.
Color corresponds to the wavelength of light waves.
The shortest light waves are "violet", the longest light waves are "red".
Answer:
B, C and D are true.
<h3>Explanation:</h3>
A is false because they appear a pale reddish colour not purple.
Answer:
Constructive interference
Explanation:
Here, the medium is same, same wavelength, same frequency, same amplitude and same direction of propagation.
Let the intensity of waves be I which is same for both
The formula for the net intensity is

where, Ф be the phase difference
So, 
Here, IR is maximum so the interference is constructive in nature.