1
JEE Main 2020 (Online) 7th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
If the magnetic field in a plane electromagnetic wave is given by
$$\overrightarrow B $$ = 3 $$ \times $$ 10-8 sin(1.6 $$ \times $$ 103x + 48 $$ \times $$ 1010t)$$\widehat j$$ T, then what will be expression for electric field ?
A
$$\overrightarrow E $$ = (9sin(1.6 $$ \times $$ 103x + 48 $$ \times $$ 1010t)$$\widehat k$$ V/m)
B
$$\overrightarrow E $$ = (60sin(1.6 $$ \times $$ 103x + 48 $$ \times $$ 1010t)$$\widehat k$$ V/m)
C
$$\overrightarrow E $$ = (3 $$ \times $$ 10-8 sin(1.6 $$ \times $$ 103x + 48 $$ \times $$ 1010t)$$\widehat i$$ V/m)
D
$$\overrightarrow E $$ = (3 $$ \times $$ 10-8 sin(1.6 $$ \times $$ 103x + 48 $$ \times $$ 1010t)$$\widehat j$$ V/m)
2
JEE Main 2020 (Online) 7th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The current I1 (in A) flowing through 1 $$\Omega $$ resistor in the following circuit is : JEE Main 2020 (Online) 7th January Morning Slot Physics - Current Electricity Question 265 English
A
0.4
B
0.25
C
0.2
D
0.5
3
JEE Main 2020 (Online) 7th January Morning Slot
Numerical
+4
-0
Change Language
A non-isotropic solid metal cube has coefficients of linear expansion as :
5 $$ \times $$ 10-5/oC along the x-axis and 5 $$ \times $$ 10-6/oC along the y and the z-axis. If the coefficient of volume expansion of the solid is C $$ \times $$ 10-6/oC then the value of C is
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4
JEE Main 2020 (Online) 7th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
JEE Main 2020 (Online) 7th January Morning Slot Physics - Capacitor Question 125 English A parallel plate capacitor has plates of area A separated by distance 'd' between them. It is filled with a dielectric which has a dielectric constant that varies as k(x) = K(1 + $$\alpha $$x) where 'x' is the distance measured from one of the plates. If (ad) << 1, the total capacitance of the system is best given by the expression :
A
$${{A{ \in _0}K} \over d}\left( {1 + {{\left( {{{\alpha d} \over 2}} \right)}^2}} \right)$$
B
$${{A{ \in _0}K} \over d}\left( {1 + {{\alpha d} \over 2}} \right)$$
C
$${{A{ \in _0}K} \over d}\left( {1 + {{{\alpha ^2}{d^2}} \over 2}} \right)$$
D
$${{A{ \in _0}K} \over d}\left( {1 + \alpha d} \right)$$

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