Physics | NEET Entrance Exam | Under Graduate Entrance Exams Online Objective Test

Under Graduate Entrance Exams NEET Entrance Exam # Physics Current Electricity Prepare / Learn

Q1. If the length of the filament of a heater is reduced by 10% the power of the heater will

A. increase by about 19%

B. Increase by about 11%

C. decrease by about 29%

D. Increase by about 9%

Answer : Option B
Explaination / Solution:

The power is related to resistance as,

$\begin{array}{l} P \propto \frac{1}{R} \\ \frac{P_{2}}{P_{1}} = \frac{R_{1}}{R_{2}} \\ a l s o, R \propto L \\ ∴ \frac{P_{2}}{P_{1}} = \frac{L_{1}}{L_{2}} \\ \frac{P_{2}}{P_{1}} = \frac{L}{0.9 L} \\ \Rightarrow P_{2} \approx 0.11 P_{1} \end{array}$

So Power increases by 11%.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Oscillations Prepare / Learn

Q2. In forced oscillations apart from acceleration forces, damping and spring forces there is

A. An external exciting force that changes the energy

B. Gravitational force acting in the line of action

C. Centripetal attractive force

D. Restoring force

Answer : Option A
Explaination / Solution:

The free damping oscillations contains the forces as acceleration forces, damping and spring forces, But in the case of forced oscillations there is an external force that acts to maintain the vibrations that usually gets damped due to presence of the damping forces like friction, air drag etc. the presence of the force promote to the Total Mechanical Energy relations.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Wave Optics Prepare / Learn

Q3. In general the term diffraction is used

A. if single source is multiplied by scalar

B. if large number of sources is added vectorially

C. None of the above

D. if two sources are added vectorially

Answer : Option B
Explaination / Solution:
No Explaination.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Magnetism and Matter Prepare / Learn

Q4. For paramagnetic materials

A. spin magnetic moments of the electrons are zero

B. orbital and spin magnetic moments of the electrons are of the order of bohr magneton

C. orbital and spin magnetic moments of the electrons are less than zero

D. orbital magnetic moments of the electrons are zero

Answer : Option B
Explaination / Solution:
No Explaination.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Gravitation Prepare / Learn

Q5. For a circularly orbiting satellite the potential energy

A. is negative, and has a magnitude twice that of the positive kinetic energy.

B. is negative, and having a magnitude twice that of the negative kinetic energy.

C. is negative, and having a magnitude twice that of the positive kinetic energy.

D. is negative, and has a magnitude thrice that of the positive kinetic energy.

Answer : Option A
Explaination / Solution:

In case of circularly orbiting satellite,

$\begin{matrix} Potential Energy = \frac{- G M m}{r} = \frac{- L^{2}}{m r^{2}} \\ KineticEnergy = \frac{- G M m}{2 r} = \frac{L^{2}}{2 m r^{2}} \end{matrix}$

Comparing both, we can say that the potential energy is negative and has a magnitude twice that of the positive kinetic energy.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Electronic Devices Prepare / Learn

Q6. In a semiconductor, the forbidden energy gap between the valance band and the conduction band is of the order of

A. 1 GeV

B. 1 ev

C. 5 eV

D. 1 MeV

Answer : Option B
Explaination / Solution:

The material which has electrical conductivity between that of a conductor and an insulator is called as semiconductor. Silicon, germanium and graphite are some examples of semiconductors.

In semiconductors, the forbidden gap between valence band and conduction band is very small. It has a forbidden gap of about 1 electron volt (eV).

Under Graduate Entrance Exams NEET Entrance Exam # Physics Motion in A Straight Line Prepare / Learn

Q7. For uniformly accelerated motion velocity at time t is given by

A.
v= v0+ at

B. v=tv0+2a

C. v=v0+2at

D. v=tv0+a

Answer : Option A
Explaination / Solution:

Consider a particle moving along a straight line with uniform acceleration 'a'. At t = 0, let the particle be at A and $v_{o}$ be its initial velocity and when t = t, v be its final velocity.

Acceleration = $\frac{C h a n g e i n v e l o c i t y}{t i m e t a k e n}$

$=> a = \frac{v - v_{o}}{t - 0}$

=> $a t = v - v_{o}$

=> $v = v_{o} + a t$

Under Graduate Entrance Exams NEET Entrance Exam # Physics Waves Prepare / Learn

Q8. When two or more waves traverse the same medium, the displacement of any element of the medium is the algebraic sum of the displacements due to each wave. This is known as

A. the Huygens principle for waves

B. the principle of conservation of waves

C. the principle of superposition of waves

D. the principle of reciprocity of waves

Answer : Option C
Explaination / Solution:
No Explaination.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Electromagnetic Waves Prepare / Learn

Q9. Visible range of electromagnetic spectrum is

A. 400 m to 0.6 m

B. 400 mm to 0.6 mm

C. 400 µm to 0.6 µm

D. 400 nm to 0.6 nm

Answer : Option D
Explaination / Solution:
No Explaination.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Electromagnetic Induction Prepare / Learn

Q10. The self-inductance of a long solenoid, the core of which consists of a magnetic material of permeability μr,turns per unit length n,length l and area A is given by

A. μrμ0n2Al

B. μrμ0n2Al2

C. μ0n2Al

D. μrn2Al

Answer : Option A
Explaination / Solution:

$L = \frac{μ N^{2} A}{l}$

N = total no. of turns

if n = no. of turns per unit length then

N = nl

$\begin{aligned} L = μ n^{2} A l \\ μ = μ_{0} μ_{r} \\ L = μ_{r} μ_{0} n^{2} A l \end{aligned}$

Physics - Online Test

$=> a = \frac{v - v_{o}}{t - 0}$

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=>a=v−vot−0

$=> a = \frac{v - v_{o}}{t - 0}$