NEET 2020: Check important questions & answers for NEET 2020 preparation. According to MHRD secretary Amit Khare, the decision to reschedule the National Eligibility cum Entrance Test (NEET) will be done based on the situation. As per the reports, 15,00,000+ students have registered for the NEET UG 2020. In this article, we have provided chapter-wise important questions for the preparation of the Physics section of NEET 2020. Most of the questions given here are based on chapters of Class 12 Physics NCERT textbooks.
Important questions & answers for preparation NEET from Physics section are given below:
Q. How many electrons are there in ‒1 coulomb?
a) 6.25 × 1018
b) 62.5 × 1018
c) 6.023 × 1023
d) 1.6 × 10-19
As, q = n e.
Given, q = 1 C, e = 1.6 × 10‒19 C and n =?
Therefore, n = 0.625 × 1019 = 6.25 × 1018.
Q. VA and VB are two points on a curved equipotential surface then,
a) VA> VB
b) VA< VB
c) VA= VB
d) Relation between the two can’t be predicted
All points in an equipotential surface have the same potential. Therefore, VA = VB.
Q. 100 joule of work is performed in carrying a charge of ‒5 coulomb from infinity to a particular point in a uniform electrostatic field. The potential of this point is:
a) 100 V
b) 5 V
d) 20 V
Charge = q = ‒ 5 C, work done = W = 100 Joule.
Let V be the potential then,
As, W = q × V ⇒ 100 = ‒ 5 × V ⇒ V = ‒ 20 V.
Q. A hollow metal sphere of radius 10 cm is charged such that the potential on its surface is 80 volt. The potential at the centre of the sphere is:
a) 8 volt
b) 800 volt
c) 80 volt
The potential at any point inside the charged metallic hollow sphere is equal to the potential at its surface. Hence, potential at its centre is 80 V.
Q. If 400 Ω resistance is made by adding four 100 Ω resistance of tolerance 5%, then the tolerance of the combination is
If four resistances of 100Ω and tolerance 5% are connected in series then, total resistance will be 400 Ω but tolerance will remain 5%.
Q. Resistance n, each of r Ω, when connected in parallel give an equivalent resistance of R Ω. If these resistances were connected in series, the combination would have a resistance in Ω, equal to
(b) R / n2
(c) R / n
When n resistors of resistance r are combined in parallel then their equivalent resistance is given by (r/n) = R ⇒ r = n R.
When n resistors of resistance R are combined in series then their equivalent resistance is given by n r ⇒ n (n R) ⇒ n2R.
Q. A copper wire is stretched to make it 0.2%. What is the percentage change in its resistivity?
(a) 0.4 %
(b) 2.0 %
(c) 4.0 %
(d) None of these
There will be no change in its resistivity because the resistivity of a material depends on the nature of the material and temperature of its surroundings.
Q. What is the value of angle of dip at the magnetic equator?
(d) Nearly 30o
The value of the angle of dip at the magnetic equator is zero degree.
Q. A bar-magnet falls down through a conducting coil as shown in the figure given below. The acceleration of the bar magnet is:
(a) less than g
(b) greater than g
(c) equal to g
Acceleration of the bar magnet will be less than ‘g’.
When the magnet falls down, an induced current is produced in the coil, due to which magnetic field will be produced in such a way that it opposes the freely falling magnet (Lenz’s law).
As the magnet falls down the ring, then current will be induced in the opposite direction, due to which the magnetic field will be produced in such a way that it again opposes the free fall of the magnet (Lenz’s law).
Q. The magnetic flux threading a coil changes from 12 Wb to 6 Wb in 1 second. What is the value of induced emf?
(a) 3 volt
(b) ‒ 3 volt
(c) 6 volt
(d) ‒ 6 volt
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