1
JEE Main 2019 (Online) 10th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A heat source at T = 103 K is connected to another heat reservoir at T = 102 K by a copper slab which is 1 mthick. Given that the thermal conductivity of copper is 0.1 WK–1m–1, the energy flux through it in the steady state is -
A
200 Wm$$-$$2
B
65 Wm$$-$$2
C
120 Wm$$-$$2
D
90 Wm$$-$$2
2
JEE Main 2019 (Online) 10th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
If the magnetic field of a plane electromagnetic wave is given by (the speed of light = 3 × 108 B = 100 × 10–6 sin $$\left[ {2\pi \times 2 \times {{10}^{15}}\left( {t - {x \over c}} \right)} \right]$$ then the maximum electric field associated with it is -
A
4.5 $$ \times $$ 104 N/C
B
4 $$ \times $$ 104 N/C
C
6 $$ \times $$ 104 N/C
D
3 $$ \times $$ 104 N/C
3
JEE Main 2019 (Online) 10th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A homogeneous solid cylindrical roller of radius R and mass M is pulled on a cricket pitch by a horizontal force. Assuming rolling without slipping, angular acceleration of the cylinder is -
A
$${F \over {2mR}}$$
B
$${2F \over {3mR}}$$
C
$${3F \over {2mR}}$$
D
$${F \over {3mR}}$$
4
JEE Main 2019 (Online) 10th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A satellite is moving with a constant speed v in circular orbit around the earth. An object of mass ‘m’ is ejected from the satellite such that it just escapes from the gravitational pull of the earth. At the time of ejection, the kinetic energy of the object is -
A
mv2
B
$${1 \over 2}$$ mv2
C
$${3 \over 2}$$ mv2
D
2 mv2

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