PHYSICS  UNIT TEST SOLUTION

Q1-Prove the equivalent resistance in series?

here,the current flowing throughout is same but voltage is different at every resistance

            total voltage= T.V

     Voltage on R1=  V1

     Voltage on R2=V2

     Voltage on R3=V3

Since we know that here 

T.V=V1+V2+V3      _1

Also V=IR

So.we can write 1 as

t(IR)= 1(IR)+2(IR)+3(IR)                               {here t means total}

t(IR)=I(R1+R2+R3)

t(IR)/I= R1+R2+R3                   {I cancels with I}

So,T.R=R1+R2+R3

           hence proved

Q2-Define resistance of the conductor
ANS-Resistance of a conductor is the obstraction in the path of the current.

Q3-What is the mathematical representation of Ohm's law?

ANS- Mathematically,the representation of Ohm's law is V=IR

Q4-What is the effect on the resistance when the length and the area of the ire is changed?

ans- Since we know that

         R= ρ(L/A)             {here L=length and A =area]

so,R∝L AND R 1/∝ A

So if length is changed then resistance changes likewise.  If 

area is decreased then resistance increases and if area is increased then  resistance increases