1
JEE Main 2019 (Online) 9th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
In a car race on straight road, car A takes a time t less than car B at the finish and passes finishing point with a speed '$$\upsilon $$' more than that of car B. Both the cars start from rest and travel with constant acceleration a1 and a2 respectively. Then '$$\upsilon $$' is equal to :
A
$${{2{a_1}{a_2}} \over {{a_1} + {a_2}}}t$$
B
$$\sqrt {2{a_1}{a_2}} t$$
C
$$\sqrt {{a_1}{a_2}} t$$
D
$${{{a_1} + {a_2}} \over 2}t$$
2
JEE Main 2019 (Online) 9th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The magnetic field associated with a light wave is given, at the origin, by B = B0 [sin(3.14 $$ \times $$ 107)ct + sin(6.28 $$ \times $$ 107)ct]. If this light falls on a silver plate having a work function of 4.7 eV, what will be the maximum kinetic energy of the photo electrons ?
(Take c = 3 $$ \times $$ 108 ms$$-$$1, h = 6.6 $$ \times $$ 10$$-$$34J-s)
A
6.82 eV
B
12.5 eV
C
8.52 eV
D
7.72 eV
3
JEE Main 2019 (Online) 9th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The position co-ordinates of a particle moving in a 3-D coordinate system is given by
x = a cos$$\omega $$t
y = a sin$$\omega $$t and
z = a$$\omega $$t

The speed of the particle is :
A
$$\sqrt 2 \,a\omega $$
B
$$a\omega $$
C
$$\sqrt 3 \,a\omega $$
D
2a$$\omega $$
4
JEE Main 2019 (Online) 9th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Ge and Si diodes start conducting at 0.3 V and 0.7 V respectively. In the following figure if Ge diode connection are reversed, the value of V0 changes by : (assume that the Ge diode has large breakdown voltage)

JEE Main 2019 (Online) 9th January Evening Slot Physics - Semiconductor Question 154 English
A
0.8 V
B
0.6 V
C
0.2 V
D
0.4 V
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