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

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

Q1. A gas expands from I to F along three possible paths, as indicated in Figure. Calculate the work in joules done by the gas along the paths IAF, IF, and IBF

A. 810 J, 506 J, 203 J

B. 840 J, 536 J, 233 J

C. 820 J, 516 J, 213 J

D. 830 J, 526 J, 223 J

Answer : Option A
Explaination / Solution:

Work done by gas = area under P-V curve

Under Graduate Entrance Exams NEET Entrance Exam # Physics Laws of Motion Prepare / Learn

Q2. A nucleus is at rest in the laboratory frame of reference. If it disintegrates into two smaller nuclei

A. the products must move at an angle in opposite directions.

B. the products must move in opposite directions.

C. the products must move in same direction.

D. the products must move at an angle in same direction.

Answer : Option B
Explaination / Solution:

Let, M = mass of nucleus at rest . m1 and m2 are masses of two smaller nuclei. v1 and v2 are the velocities of respective masses

Now, According to the law of conservation of momentum,

Initial momentum before disintegration = final momentum after disintegration

$m_{1} v_{1} + m_{2} v_{2} = 0$

$v_{2} = - \frac{m_{2}}{m_{1}} \cdot v_{1}$

As masses $m_{1}$ and $m_{2}$ cannot be negative, $v_{1}$ and $v_{2}$ having opposite signs and so the two smaller nuclei move in opposite directions.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Work Energy and Power Prepare / Learn

Q3. A 50.0-kg marathon runner runs up the stairs to the top of a 443-m-tall Tower. To lift herself to the top in 15.0 minutes, what must be her average power output?

A. 241 W

B. 221 W

C. 201 W

D. 261 W

Answer : Option A
Explaination / Solution:

P=WtW=mgh=50×9.8×443t=15×60secP=50×9.8×44315×60=241W

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

Q4. orders of magnitude of random electron motion speed to drift speed are like

A. 106m/s,10−4m/s

B. 102m/s,102m/s

C. 104m/s,10−2m/s

D. 103m/s,10−1m/s

Answer : Option A
Explaination / Solution:

The random velocities of electrons is of the order 105 to 106 m/s, while the drift velocities are of the order 0.1mm/s (10-4m/s)

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

Q5. Find the kinetic, potential, and total energies of the hydrogen atom in the first excited level, and find the wavelength of the photon emitted in a transition from that level to the ground level.

K_{2}

= 3.80 eV, U2 =-6.80 eV and

E_{2}

= -3.40 eV. For the ground level (n = 1)

E_{1}

= -13.6 eV,

λ

= 132 nm

K_{2}

= 3.60 eV,

U_{2}

=-6.80 eV and

E_{2}

= -3.40 eV. For the ground level (n = 1)

E_{1}

= -13.6 eV,

λ

= 129 nm

K_{2}

= 3.40 eV,

U_{2}

=-6.80 eV and

E_{2}

= -3.40 eV. For the ground level (n = 1)

E_{1}

= -13.6 eV,

λ

= 122 nm

K_{2}

= 3.90 eV, U2 =-6.80 eV and

E_{2}

= -3.40 eV. For the ground level (n = 1)

E_{1}

= -13.6 eV,

λ

= 142 nm

Answer : Option C
Explaination / Solution:
No Explaination.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Electrostatic Potential and Capacitance Prepare / Learn

Q6. The effective capacitance of two capacitors of capacitances C1 and C2 (with C2 > C1) connected in parallel is 25/6 times the effective capacitance when they are connected in series. The ratio C2/C1 is

A. -4/3

B. -25/6

C. -5/3

D. -3/2

Answer : Option D
Explaination / Solution:

Given

\frac{C_{p}}{C_{s}} = \frac{25}{6}

, then

C_{p} = 25 k; C_{s} = 6 k

where k is a constant.

Solving ,

C_{2} = 15 k; C_{1} = 10 k; and \frac{C_{2}}{C_{1}} = \frac{3}{2}

Under Graduate Entrance Exams NEET Entrance Exam # Physics System of Particles and Rotational Motion Prepare / Learn

Q7. The moment of inertia of a solid sphere of density ρ and radius R is given by

A. 176105ρR3

B. 176105ρR5

C. 105176ρR2

D. 176105ρR2

Answer : Option B
Explaination / Solution:

$\begin{aligned} I = \frac{2}{5} (M R^{2}) \\ = \frac{2}{5} [(\frac{4}{3} π R^{3}) . ρ . R^{2}] \\ = \frac{2}{5} [(\frac{4}{3} \frac{22}{7} R^{3}) . ρ . R^{2}] \end{aligned}$ As Mass = Density x Volume of Sphere

$= \frac{176}{105} ρ R^{5}$

Under Graduate Entrance Exams NEET Entrance Exam # Physics Mechanical Properties of Fluids Prepare / Learn

Q8. The unit of surface tension in S.I units is given by

A. Newtons per

m e t e r^{2}

B. dynes per cm

C. Newtons per

m e t e r^{2}

D. dynes per

c m^{2}

Answer : Option C
Explaination / Solution:

surface tension is measured in force per unit length. The S.I unit is newton per meter but the CGS unit dyne per centimeter is also used.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Physical World Prepare / Learn

Q9. The fundamental force with the shortest range is

A. Gravitational Force

B. Strong Nuclear Force

C. Weak Nuclear Force

D. Electromagnetic Force

Answer : Option C
Explaination / Solution:

There are four fundamental forces in nature which are Gravitational force, Strong force, Weak force and Electromagnetic force.

Gravitational Force: This force is the weakest but has an infinite range.

Strong Nuclear force: This force holds the nucleus of an atom together. It is the strongest of the forces. It acts over a range of about 10-15m.

Weak Nuclear Force: This force is weak compared to the strong force as the name implies and has the shortest

range of 10-18m

Electromagnetic Force: This is the second strongest force after the strong force and it acts on electrically charged particles. It has strength of 1/137 relative to the strong force but has an infinite range.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Kinetic Theory Prepare / Learn

Q10. One mole of hydrogen gas is heated at constant pressure from 300 K to 420 K. Calculate the increase in its internal energy.

A. 2.15 kJ

B. 2.65 kJ

C. 2.85 kJ

D. 2.49 kJ

Answer : Option D
Explaination / Solution:

Hydrogen is a diatomic gas. (CV = 2.5R)

Change in internal energy

$Δ U = n C_{V} Δ T = 1 \times 2.5 \times 8.31 \times 120 = 2493 J = 2.49 K J$

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