1
COMEDK 2024 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

In an inductor of self-inductance $$2 \mathrm{~mH}$$, current changes with time (in sec) according to the relation, $$I=(3 t^2-3 t+8) A$$. The emf becomes zero at

A
2 sec
B
6 sec
C
0.5 sec
D
5 sec
2
COMEDK 2024 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

A metallic rod of length '$$a$$' is rotated with an angular frequency of $$0.2 \mathrm{~rads}^{-1}$$ about an axis normal to the rod passing through its one end. A constant and uniform magnetic field of '$$\mathrm{B}$$' T parallel to the axis exists everywhere. The emf developed across the ends of the rod is

A
$$\frac{\mathrm{Ba}^2}{10}$$
B
$$\frac{\mathrm{Ba}^2}{5}$$
C
$$\frac{\mathrm{Ba}^2}{50}$$
D
$$\frac{\mathrm{Ba}^2}{2}$$
3
COMEDK 2024 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Select the unit of the coefficient of mutual induction from the following.

A
volt. second / ampere
B
weber. ampere
C
ampere / weber
D
volt. ampere / second
4
COMEDK 2024 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Around the central part of an air cored solenoid of length $$20 \mathrm{~cm}$$ and area of cross section $$1.4 \times 10^{-3} \mathrm{~m}^2$$ and 3000 turns, another coil of 250 turns is closely wound. A current $$2 \mathrm{~A}$$ in the solenoid is reversed in $$0.2 \mathrm{~s}$$, then the induced emf produced is

A
$$1.32 \times 10^{-1} \mathrm{~V}$$
B
$$4 \times 10^{-1} \mathrm{~V}$$
C
$$1.16 \times 10^{-1} \mathrm{~V}$$
D
$$8 \times 10^{-2} \mathrm{~V}$$
COMEDK Subjects
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