PHY101 Assigment # 2 2016

                                                          PHY101

                                           Assignment 2: (Spring 2016)

PHYSICS (PHY101)

TOTAL MARKS: 25

Due Date: 04/07/2016

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Question # 1

Two particles having charges q₁ = 0.600 nC and q₂ = 7.00 nC are separated by a distance of 130 cm. At what point along the line connecting the two charges is the total electric field due to the two charges equal to zero?    

Question # 2

The sum of the charges on both plates of a capacitor is zero. What does a capacitor store?  

Ans: The total charge in a capacitor is always zero and in equilibrium with its surroundings. But capacitors do store electric energy. The energy is stored in an electric field. Voltage, when applied between two plates of a capacitor, creates a potential difference between its plates.  

Question # 3

(a)   A 20 dB sound is twice as intense as a 10 dB sound, explain it.

Ans:

        L (db) =10log (l/lo)[lo=10^-12W/m^2]

The relation between two different sound levels is

L2 (db) =L1 (db) +10log (12/l1)

If l2=2l1

L2 (dB) =L1 (dB) + 10log2=L1+3dB

If intensity doubles the sound level increases of 3 dB

The above relation can be written as

l2 = l1 10^ [(L2-L1)/10]

If L2-L1=20-10=10dB

l2 = 10l1

if sound level increases of 10dB the intensity increases 10 times.

(b)   The degree of Doppler shift experienced by a listener is independent of how far the listener is from a moving sound source. Is it true or wrong explain it?  

Ans:

        Essentially wrong. The distance and velocity (speed and direction) of the source all combine to give the wave length that arrives at the listener.

Question # 4

(a)   What is Fourier analysis?

Ans:

         The process of decomposing a musical instrument sound or any other periodic function into its constituent sine or cosine waves is Fourier analysis.

(b)    What is principal of superposition?      

Ans:

        In physics and system theory, the superposition principle, also known as superposition property, states that, for all linear systems, the net responses at a given place and time caused by two or more stimuli is the sum of the responses which would have been caused by each stimulus individually.

                                                                                   

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