Explanation:
The total energy of the system remains conserved. It just converts from one form of energy to another.
The battery of the cell phone contains chemicals. As the electricity is passed through the cell phone, the electrical energy is converted to chemical energy. As she notices that the phone is warm and after the battery has been fully charged and the student unplugs her cell phone, the phone vibrates when a message arrives, this shows the conversion of chemical energy to mechanical energy, thermal energy etc.
Hence, we can say that the correct option is (b).
Answer:
The speed of the wire is 5 m/s.
Explanation:
Given that,
Length = 20 cm
Magnetic field = 0.1 T
Current = 10 mA
Resistance 
We need to calculate the speed of the wire
Using formula of emf
Using formula of current
Put the value of 
into the formula of current
Hence, The speed of the wire is 5 m/s.
Answer: 1/R = 1/R1 + 1/R2+ ...+ 1/Rn
R is resistance of system in which there are resistors R1, R2 , ... Rn parallel.
Answer:
Explanation:
Amplitude is a measure of the size of sound waves. It depends on the amount of energy that started the waves. Greater amplitude waves have more energy and greater intensity, so they sound louder.
