TS Mocktest 2021-1

1.

          

A. C is higher potential of 5 V with respect to point E
B. C is lower potential of 5 V with respect to point E
C. C is lower potential of 10 V with respect to point E
D. C is higher potential of 15 V with respect to point E

Answer : C is lower potential of 5 V with respect to point E
Explanation:-

2.
       

A. 4 A
B. 6 A
C. 8 A
D. 12 A

Answer : 6 A
Explanation:-
        

3. For the circuit given in figure. 3. the thevenin's equivalent circuit values at the terminals A and B are

A. Vth=24V,Rth=16ohms
B. Vth=24V,Rth=8ohms
C. Vth=12V,Rth=16ohms
D. Vth=12V,Rth=8ohms

Answer : Vth=12V,Rth=16ohms
Explanation:-
                           

4. An electric bulb is rated 220 V, 100 W. The power consumed by it when operated on 110 V will be

A. 75 W
B. 40 W
C. 25 W
D. 50 W

Answer : 25 W
Explanation:- Given V=220V, P=100W
R=(V^2)/P=(220*220)/100=484 ohm
Power consumed when operated on 110V is V^2/R
P110v=(110*110)/484
P110v=25 W

5. A heater coil is cut into two equal parts and only one part is now used in the heater. The heat generated will now be

A. doubled
B. four times
C. one fourth
D. halved

Answer : doubled
Explanation:-

6. An electric current is passed through a circuit containing two wires of the same material connected in parallel. If the lengths and radii of the wires are in the ratio of 4/3 and 2/3, then the ratio of currents passing through the wires will be

A. 1/2
B. 1/3
C. 8/9
D. 2

Answer :
Explanation:-
Given two wires have same type of material so specific resistance is same
Given l1/l2=4/3, r1/r2=2/3.
A=π/4(d^2)==π/4((2r)^2)==π/4(4r^2)
Here we are taking ratios so A1/A2=r1/r2
R∝l/A
R1/R2=l1/l2*(A2/A1)
R1/R2=4/3*(3/2)
R1/R2=2/1
I∝1/R
I1/I2=R2/R1
I1/I2=1/2 (R1/R2=2/1)

7. Curie temperature is the temperature above which

A. a ferromagnetic material becomes paramagnetic
B. a paramagnetic material becomes diamagnetic
C. a ferromagnetic material becomes diamagnetic
D. a paramagnetic material becomes ferromagnetic

Answer : a ferromagnetic material becomes paramagnetic
Explanation:-

8. Which one of the following is semiconductor material

A. Copper
B. Aluminium
C. Germanium
D. Rubber

Answer : Germanium
Explanation:-

9. The dielectric strength of mica at 25° c is

A. 1 kv/ mm
B. 250 kv / mm
C. 10 kv / mm
D. 80 kv / mm

Answer : 80 kv / mm
Explanation:-

10. For which of the following materials the temperature coefficient of resistance is negative

A. Copper
B. Gold
C. Silicon
D. Mercury

Answer : Silicon
Explanation:- Semiconductor materials have negative temperature coefficient of resistance ,whereas conductors have positive temperature coefficient of resistance