1
JEE Advanced 2020 Paper 1 Offline
MCQ (More than One Correct Answer)
+4
-2
Sometimes it is convenient to construct a system of units so that all quantities can be expressed in terms of only one physical quantity. In one such system, dimensions of different quantities are given in terms of a quantity X as follows: [position] = [X$$\alpha$$]; [speed] = [X$$\beta$$ ]; [acceleration] = [Xp]; [linear momentum] = [Xq]; [force] = [Xr]. Then
A
$$\alpha$$ + p = 2$$\beta$$
B
p + q - r = $$\beta$$
C
p - q + r = $$\alpha$$
D
p + q + r = $$\beta$$
2
JEE Advanced 2020 Paper 1 Offline
MCQ (More than One Correct Answer)
+4
-2
The filament of a light bulb has surface area 64 mm2 . The filament can be considered as a black body at temperature 2500 K emitting radiation like a point source when viewed from far. At night the light bulb is observed from a distance of 100 m. Assume the pupil of the eyes of the observer to be circular with radius 3 mm. Then

(Take Stefan-Boltzmann constant = 5.67 $$\times$$ 10−8 Wm−2K−4 , Wien’s displacement constant = 2.90 $$\times$$ 10−3 m-K, Planck’s constant = 6.63 $$\times$$ 10−34 Js, speed of light in vacuum = 3.00 $$\times$$ 108 ms−1)
A
power radiated by the filament is in the range 642 W to 645 W
B
radiated power entering into one eye of the observer is
in the range 3.15 $$\times$$ 10−8 W to 3.25 $$\times$$ 10−8 W
C
the wavelength corresponding to the maximum intensity of light is 1160 nm
D
taking the average wavelength of emitted radiation to be 1740 nm, the total number of photons entering per second into one eye of the observer is in the range 2.75 $$\times$$ 1011 to 2.85 $$\times$$ 1011
3
JEE Advanced 2020 Paper 1 Offline
MCQ (More than One Correct Answer)
+4
-2
A uniform electric field, $$\overrightarrow E = - 400\sqrt 3 \widehat y$$ NC−1 is applied in a region. A charged particle of mass m carrying positive charge q is projected in this region with an initial speed of 2$$\sqrt {10}$$ $$\times$$ 106 ms−1 . This particle is aimed to hit a target T, which is 5 m away from its entry point into the field as shown schematically in the figure.
Take $${q \over m}$$ = 1010 Ckg−1 . Then
A
the particle will hit T if projected at an angle 45o from the horizontal
B
the particle will hit T if projected either at an angle 30o or 60o from the horizontal
C
time taken by the particle to hit T could be $$\sqrt {{5 \over 6}}$$ $$\mu$$s as well as $$\sqrt {{5 \over 2}}$$ $$\mu$$s
D
time taken by the particle to hit T is $$\sqrt {{5 \over 3}}$$ $$\mu$$s
4
JEE Advanced 2020 Paper 1 Offline
MCQ (More than One Correct Answer)
+4
-2
Shown in the figure is a semicircular metallic strip that has thickness t and resistivity $$\rho$$. Its inner radius is R1 and outer radius is R2. If a voltage V0 is applied between its two ends, a current I flows in it. In addition, it is observed that a transverse voltage $$\Delta$$V develops between its inner and outer surfaces due to purely kinetic effects of moving electrons (ignore any role of the magnetic field due to the current). Then (figure is schematic and not drawn to scale)
A
$$I = {{{V_0}t} \over {\pi \rho }}\ln \left( {{{{R_2}} \over {{R_1}}}} \right)$$
B
the outer surface is at a higher voltage than the inner surface
C
the outer surface is at a lower voltage than the inner surface
D
$$\Delta$$V $$\propto$$ I2
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