Sponsor Area
Electric Resistance and Ohms Law
Question
When a potential difference of 3V is applied between the two ends of a 60 cm long metallic wire, current density in it is found to be 1 x 10 -7 Am 2. Find conductivity of the material of the wire in SI system.
Solution
Given,
Length of the metallic wire, L = 60 cm = 0.6 m
A = Area of the cross section of the conductor
A = Area of the cross section of the conductor
Question
Chose the correct alternative A, B, C or D
In current electricity. Ohm’s law is obeyed by all:
-
solids
-
metals
-
liquids
-
gases
solids
metals
Solution
B.
metals
Question
Name any one instrument which works on the principle of Tangent law in magnetism.
Solution
Tangent Galvanometer works on the principle of tangent law in magnetism.
Question
In the circuit shown below Figure 3, E1 and E2 are batteries having emfs 4.0 and 3.5 V respectively and internal resistance 1Ω and 2Ω respectively. Using Kirchoff s laws, calculate currents : I1, I2 and I3.
Solution
(i)
In closed circuit PQSP
I1>1 - 4I1 + 10I3 = 5 ...(1)
Applying Kirchoff s First law at pt. θ.
I3 = I1 + I2
Using the above value of I3 in equation (1)
I, + 4I 1, + 10(I1 + I2 ) = 4
151, + 10I2 = 4 ...(2)
In closed circuit RQSR
2I2 + 3I2+ 10a +I2) = 3-5
10I, + 15I2 = 3-5 -(3)
On Solving equation (2) and (3) we get
12 = 0-1 Amp., I1 = 0-2 Amp.,
13 = I, + I2
= 0-3 Amp
Sponsor Area
Mock Test Series
Mock Test Series