1
JEE Main 2020 (Online) 9th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
An electric dipole of moment
$$\overrightarrow p = \left( { - \widehat i - 3\widehat j + 2\widehat k} \right) \times {10^{ - 29}} $$ C.m is
at the origin (0, 0, 0). The electric field due to this dipole at
$$\overrightarrow r = + \widehat i + 3\widehat j + 5\widehat k$$ (note that $$\overrightarrow r .\overrightarrow p = 0$$ ) is parallel to :
A
$$\left( { + \widehat i + 3\widehat j - 2\widehat k} \right)$$
B
$$\left( { + \widehat i - 3\widehat j - 2\widehat k} \right)$$
C
$$\left( { - \widehat i + 3\widehat j - 2\widehat k} \right)$$
D
$$\left( { - \widehat i - 3\widehat j + 2\widehat k} \right)$$
2
JEE Main 2020 (Online) 9th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Three harmonic waves having equal frequency $$\nu $$ and same intensity $${I_0}$$, have phase angles 0, $${\pi \over 4}$$ and $$ - {\pi \over 4}$$ respectively. When they are superimposed the intensity of the resultant wave is close to :
A
5.8 I0
B
3 I0
C
0.2 I0
D
I0
3
JEE Main 2020 (Online) 9th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A charged particle of mass 'm' and charge 'q' moving under the influence of uniform electric field $$E\overrightarrow i $$ and a uniform magnetic field $$B\overrightarrow k $$ follows a trajectory from point P to Q as shown in figure. The velocities at P and Q are respectively, $$v\overrightarrow i $$ and $$ - 2v\overrightarrow j $$ . Then which of the following statements (A, B, C, D) are the correct ?
(Trajectory shown is schematic and not to scale) : JEE Main 2020 (Online) 9th January Morning Slot Physics - Magnetic Effect of Current Question 128 English
(A) E = $${3 \over 4}\left( {{{m{v^2}} \over {qa}}} \right)$$

(B) Rate of work done by the electric field at P is $${3 \over 4}\left( {{{m{v^3}} \over a}} \right)$$

(C) Rate of work done by both the fields at Q is zero

(D) The difference between the magnitude of angular momentum of the particle at P and Q is 2mav.
A
(A), (B), (C), (D)
B
(A), (B), (C)
C
(A), (C), (D)
D
(B), (C), (D)
4
JEE Main 2020 (Online) 9th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Which of the following is an equivalent cyclic process corresponding to the thermodynamic cyclic given in the figure ? where, 1 $$ \to $$ 2 is adiabatic.
(Graphs are schematic and are not to scale) JEE Main 2020 (Online) 9th January Morning Slot Physics - Heat and Thermodynamics Question 258 English
A
JEE Main 2020 (Online) 9th January Morning Slot Physics - Heat and Thermodynamics Question 258 English Option 1
B
JEE Main 2020 (Online) 9th January Morning Slot Physics - Heat and Thermodynamics Question 258 English Option 2
C
JEE Main 2020 (Online) 9th January Morning Slot Physics - Heat and Thermodynamics Question 258 English Option 3
D
JEE Main 2020 (Online) 9th January Morning Slot Physics - Heat and Thermodynamics Question 258 English Option 4
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