Physics - Online Test

Under Graduate Entrance Exams NEET Entrance Exam Physics TEST : 123

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

Q1. When a capacitor is connected to a battery

A. an alternating current flows in the circuit.

B. a current flows in the circuit for sometime and then decreases to zero

C. no current flows in the circuit at all

D. the current keeps on increasing, reaching a maximum value when the

Answer : Option B
Explaination / Solution:

When an uncharged capacitor is connected to a battery, charges flow from the poles of the battery to the plates of the capacitor and this process continues till the potential across the capacitor attains the potential difference of the battery. The current flows in the circuit till the time the capacitor is charged and then it ceases.

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

Q2. Strong Nuclear Force has

A. long range compared to gravitational forces

B. long range compared to electrical forces

C. short range compared to electromagnetic forces

D. is exerted by electromagnetic fields

Answer : Option C
Explaination / Solution:

Strong Nuclear Force : The nucleus is held by the forces which protect them from the enormous repulsion forces of the positive protons. It is a force with short range and not similar to the electromagnetic force. We know that the nucleus is made up with its fundamental particles that are the protons and neutrons. These are formed with quarks which are held together with strong force. This strong force is residual color force. The basic exchange particle is called gluon which works as mediator forces between quarks. Both the particles; gluons and quarks are present in protons and neutrons.

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

Q3. A boy comes running and sits on a merry-go-round. What is conserved?

A. Angular momentum

B. Kinetic energy of rotation

C. None of these

D. Linear momentum

Answer : Option A
Explaination / Solution:

According to law of conservation of angular momentum if no external torque is applied on a body in rotation than its angular momentum remains conserved.

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

Q4. A liquid drop of radius R is broken up into N small droplets. The work done is proportional to

A. N

^{- 2 / 3}

C. N

^{- 0. 5}

D. N

^{- 2 / 3}

Answer : Option D
Explaination / Solution:
No Explaination.

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

Q5. What is the root-mean-square speed of helium atoms in a balloon of diameter 30.0 cm at 20.0

^{\circ}

C and 1.00 atm?

A. 1.15 km/s

B. 1.35 km/s

C. 1.57 km/s

D. 1.49 km/s

Answer : Option B
Explaination / Solution:

vrms=3RTM−−−−√=3×8.31×2934×10−3−−−−−−−−√=1351m/sec=1.35Km/sec

Under Graduate Entrance Exams NEET Entrance Exam # Physics Ray Optics and Optical Instruments Prepare / Learn

Q6. A person can see clearly only up to a distance of 30 cm. He wants to read a book placed at a distance of 50 cm from his eyes. What is the power of the lens he requires for his spectacles?

A. -1.33 D

B. -1.67 D

C. -1.0 D

D. -2.0 D

Answer : Option A
Explaination / Solution:
No Explaination.

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

Q7. The process of fusion is used in the construction of

A. a hydrogen bomb

B. an atom bomb

C. an ordinary bomb

D. a neutron bomb

Answer : Option A
Explaination / Solution:
No Explaination.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Thermal Properties of Matter Prepare / Learn

Q8.

A child running a temperature of 101 $^{\circ}$ F is given an antipyrin (i.e. a medicine that lowers fever) which causes an increase in the rate of evaporation of sweat from his body. If the fever is brought down to 98 $^{\circ}$ F in 20 min, what is the average rate of extra evaporation caused, by the drug? Assume the evaporation mechanism to be the only way by which heat is lost. The mass of the child is 30 kg. The specific heat of human body is approximately the same as that of water, and latent heat of evaporation of water at that temperature is about 580 cal $g^{- 1}$

g^{- 1}

A. 5.2 g/min

B. 4.6 g/min

C. 4.3 g/min

D. 4.9 g/min

Answer : Option C
Explaination / Solution:

$Δ T = 101 - 98 = 3^{\circ} F = {(3 \times \frac{5}{9})}^{\circ} C$

Specific heat of the human body = Specific heat of water = 1000 cal/kg/ °C

The heat lost by the child is $Q = m c Δ T = 30 \times 1000 \times (3 \times \frac{5}{9}) = 50000 c a l$

Let m1 be the mass of the water evaporated from the child’s body in 20 min.
Loss of heat through water is

$\begin{aligned} Q = m_{1} L \\ m_{1} = \frac{Q}{L} = \frac{50000}{580} = 86.2 g m \end{aligned}$

Average rate of extra evaporation caused by the drug = m1 / t
= 86.2 / 200
= 4.3 g/min.

Under Graduate Entrance Exams NEET Entrance Exam # Physics Units and Measurements Prepare / Learn

Q9. The number of significant digits in 0.0006032

m^{2}

A. 4

B. 6

C. 3

D. 5

Answer : Option A
Explaination / Solution:

There are three rules on determining how many significant figures are in a number:

Non-zero digits are always significant.
Any zeros between two significant digits are significant.
A final zero or trailing zeros in the decimal portion ONLY are significant.

So keeping these rules in mind, there are 4 significant digit

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

Q10. Inductance of an inductor whose reactance is 120 Ω at 80.0 Hz is

A. 0.239 H

B. 0.219 H

C. 0.209 H

D. 0.199 H

Answer : Option A
Explaination / Solution:

XL=120Ωf=80HzXL=ωL=2πfLL=XL2πf=1202×3.14×80=0.239H

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Under Graduate Entrance Exams NEET Entrance Exam Physics TEST : 123