1
JEE Main 2018 (Online) 15th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A Helmholtz coil has a pair of loops, each with $$N$$ turns and radius $$R$$. They are placed coaxially at distance $$R$$ and the same current $${\rm I}$$ flows through the loops in the same direction. $$P,$$ midway between the centers $$A$$ and $$C$$, is given by [Refer to figure given below] :

JEE Main 2018 (Online) 15th April Morning Slot Physics - Magnetic Effect of Current Question 186 English
A
$${{8N{\mu _0}{\rm I}} \over {{5^{1/2}}R}}$$
B
$${{8N{\mu _0}{\rm I}} \over {{5^{3/2}}R}}$$
C
$${{4N{\mu _0}{\rm I}} \over {{5^{1/2}}R}}$$
D
$${{4N{\mu _0}{\rm I}} \over {{5^{3/2}}R}}$$
2
JEE Main 2018 (Online) 15th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Light of wavelength $$550$$ $$nm$$ falls normally on a slit of width $$22.0 \times {10^{ - 5}}$$ $$cm.$$ The angular position of the second minima from the central maximum will (in radians) :
A
$${\pi \over {12}}$$
B
$${\pi \over 8}$$
C
$${\pi \over 6}$$
D
$${\pi \over 4}$$
3
JEE Main 2018 (Online) 15th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A monochromatic beam of light has a frequency $$v = {3 \over {2\pi }} \times {10^{12}}Hz$$ and is propagating along the direction $${{\widehat i + \widehat j} \over {\sqrt 2 }}.$$
It is polarized along the $$\widehat k$$ direction. The acceptable form for the magnetic field is :
A
JEE Main 2018 (Online) 15th April Morning Slot Physics - Electromagnetic Waves Question 141 English Option 1
B
JEE Main 2018 (Online) 15th April Morning Slot Physics - Electromagnetic Waves Question 141 English Option 2
C
JEE Main 2018 (Online) 15th April Morning Slot Physics - Electromagnetic Waves Question 141 English Option 3
D
JEE Main 2018 (Online) 15th April Morning Slot Physics - Electromagnetic Waves Question 141 English Option 4
4
JEE Main 2018 (Online) 15th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A body of mass $$M$$ and charge $$q$$ is connected to spring of spring constant $$k.$$ It is oscillating along $$x$$-direction about its equilibrium position, taken to be at $$x=0,$$ with an amplitude $$A$$. An electric field $$E$$ is applied along the $$x$$-direction. Which of the following statements is correct ?
A
The new equilibrium position is at a distance $${{qE} \over {2k}}$$ from $$x=0.$$
B
The total energy of the system is $${1 \over 2}m{\omega ^2}{A^2} + {1 \over 2}{{{q^2}{E^2}} \over k}.$$
C
The total energy of the system is $${1 \over 2}m{\omega ^2}{A^2} - {1 \over 2}{{{q^2}{E^2}} \over k}.$$
D
The new equilibrium position is at a distance $${{2qE} \over k}$$ from $$x=0.$$
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