1
KCET 2019
MCQ (Single Correct Answer)
+1
-0

An antenna uses electromagnetic waves of frequency $$5 \mathrm{~MHz}$$. For proper working, the size of the antenna should be

A
15 m
B
300 m
C
15 km
D
3 km
2
KCET 2019
MCQ (Single Correct Answer)
+1
-0

A magnetic needle has a magnetic moment of $$5 \times 10^{-2} \mathrm{~Am}^2$$ and moment of inertia $$8 \times 10^{-6} \mathrm{~kgm}^2$$. It has a period of oscillation of $$2 \mathrm{~s}$$ in a magnetic field $$\mathbf{B}$$. The magnitude of magnetic field is approximately?

A
$$1.6 \times 10^{-4} \mathrm{~T}$$
B
$$0.4 \times 10^{-4} \mathrm{~T}$$
C
$$3.2 \times 10^{-4} \mathrm{~T}$$
D
$$0.8 \times 10^{-4} \mathrm{~T}$$
3
KCET 2019
MCQ (Single Correct Answer)
+1
-0

A toroid has 500 turns per meter length. If it carries a current of $$2 \mathrm{A}$$, the magnetic energy density inside the toroid is

A
$$0.628 \mathrm{~J} / \mathrm{m}^3$$
B
$$0.314 \mathrm{~J} / \mathrm{m}^3$$
C
$$6.28 \mathrm{~J} / \mathrm{m}^3$$
D
$$3.14 \mathrm{~J} / \mathrm{m}^3$$
4
KCET 2019
MCQ (Single Correct Answer)
+1
-0

Consider the situation given in figure. The wire $$A B$$ is slid on the fixed rails with a constant velocity. If the wire $$A B$$ is replaced by a semicircular wire, the magnitude of the induced current will

KCET 2019 Physics - Electromagnetic Induction Question 10 English

A
increase
B
remain same
C
decrease
D
increase or decrease depending on whether the semicircle bulges towards the resistance or away from it.
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