RBSE Class 12 Physics Chapter 5 Text Book Exercise with Answers
RBSE Class 12 Physics Chapter 5 Multiple Choice Type Questions
RBSE Solutions Question 1.
The product of resistivity and conductivity of conductor depends upon :
(a) the cross-sectional area
(b) the temperature
(c) the length
(d) none of these
Answer:
(d) none of these
RBSE Solutions Question 2.
Two wires of same shape whose resistivity ρ1and ρ2 are connected in series. The equivalent resistivity of the combination will be :
(a) p1ρ2−−−−√
(b) 2 (ρ1 + ρ2)
(c) ρ1+ρ22
(d) ρ1 + ρ2
Answer:
(c) ρ1+ρ22
Resistance in series
Physics Class 12 RBSE Solutions Question 3.
A conducting resistance is connected to the battery and temperature of conductor decreases by the process of cooling then the value of current will be :
(a) increased
(b) decreased
(c) remain constant
(d) zero
Answer:
(a) increased
The resistance of the conducting wire will decrease according to equation Rt = R0 (1 ± α Δt) due to which current will increase according to Ohm’s law (I = VR)
Question 4.
A cell of e.m.f. 2.1 V gives a current of 0.2 A. This current is passing through the resistance of 10 Ω. The internal resistance of cell is :
(a) 0.2 Ω
(b) 0.5 Ω
(c) 0.8 Ω
(d) 0 Ω
Answer:
(b) 0.5 Ω
Question 5.
The current I and voltage V curves for a given metallic conductor at two different temperatures T1 and T2 are shown in the figure then :
(a) T1 = T2
(b) T1 > T2
(c) T1 < T2
(d) None of these
Answer:
(c) T1 < T2
Gradient of graph,
tanθ = 1R=IV
But, according to equation Rt = R0 (1 α Δt)
∴ The resistance R2 > R1
∴ T2 > T1
Question 6.
The electric power is supplied through the copper wires from a one city to another city which is 150 km apart. If the terminal voltage and average resistance of per kilometer are 8 volt and 0.5 Ω respectively then the power loss in a wire is :
(a) 19.2 W
(b) 19.2 kW
(c) 19.2 J
(d) 12.2 kW
Answer:
(b) 19.2 kW
Total resistance of wire = 0.5 × 150 km = 75 Ω
Potential drop on wire = 8 × 150 = 1200 volt
Power loss m wire (P) = V2R=1200×120075
= 19200 watts = 19.2 kW
Question 7.
Five resistances of R Ω were taken. First three resistances are connected in parallel combination and rest two are connected in series combination, then the equivalent resistance is :
Answer:
(b)
Equivalent resistance,
RBSE Solution
Question 8.
Drift velocity (vd) depends upon the electric field, in which the following dependence of drift velocity on the electric field obey the ohm’s law is :
(a) vd ∝ E2
(b) vd ∝ E
(c) vd ∝ E1/2
(d) vd = constant
Answer:
(b) vd ∝ E
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