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

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

Q1. The number of valence electrons in a good conductor is generally

A. five

B. six or more than six

C. four

D. three or less than three

Answer : Option D
Explaination / Solution:

The electron theory states that all matter is composed of atoms and the atoms are composed of smaller particles called protons, electrons, and neutrons. The electrons orbit the nucleus which contains the protons and neutrons. It is the valence electrons that we are most concerned with in electricity. These are the electrons which are easiest to break loose from their parent atom. Normally, conductors have three or less valence electrons; insulators have five or more valence electrons; and semiconductors usually have four valence electrons.

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

Q2. A bus start from rest with an acceleration of 1 m/sec2. A man who is 48 meter behind the bus with a uniform velocity of 10 m/sec. then the minimum time after which the man will catch the bus is

A. 8 sec

B. 14 sec

C. 4 sec

D. 10 sec

Answer : Option A
Explaination / Solution:

Let the distance traveled by the bus when man catch the bus be S meter distance traveled by the man when he catch the bus S'=S+48 meter

Given :

Initial velocity of bus u=0

Initial velocity of man u'=10m/sec Acceleration of Bus=1 m/s2

Accelerationof Man=0

We will use formula for displacement

$S = u t + \frac{1}{2} a t^{2}$

By substituting the values in above equation we get,

Displacement of Bus $S = \frac{1}{2} t^{2} . . . . . . (1)$

Displacement of Man $S + 48 = 10 t . . . . . . . (2)$

By substituting the value of S from eq(1) in eq(2)we get

$\frac{1}{2} t^{2} + 48 = 10 t$

$=> t^{2} - 20 t + 96 = 0$

$=> t^{2} - 12 t - 8 t + 96 = 0$

$=> (t - 8) (t - 12) = 0$

=> t = 8, 12

Taking minimum value t = 8 sec

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

Q3. 56 tuning forks are arranged in a series that each fork gives 4 beats/sec, with the previous one. The frequency of last fork is 3 times that of first. Then frequency of first fork is

A. 110 Hz

B. 56 Hz

C. 52 Hz

D. 60 Hz

Answer : Option A
Explaination / Solution:
No Explaination.

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

Q4. Suppose that the electric field amplitude of an electromagnetic wave is

E_{0}

= 120 N/C and that its frequency is ν = 50.0 MHz

B_{0}

ω

, k, and

λ

. are

A. 500 nT, 3.3 ×× 108 rad/s, 1.05 rad/m, 6.00 m

B. 450 nT, 3.0 ×× 108 rad/s, 1.05 rad/m, 6.00 m

C. 550 nT, 3.14 ×× 108 rad/s, 1.05 rad/m, 6.00 m

D. 400 nT, 3.14 ×× 108 rad/s, 1.05 rad/m, 6.00 m

Answer : Option D
Explaination / Solution:
No Explaination.

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

Q5.

A horizontal straight wire 10 m long extending from east to west is falling with a speed of 5.0 m $s^{- 1}$ , at right angles to the horizontal component of the earth’s magnetic field, $0. 30 \times 10 - 4$ Wb m-2. Instantaneous value of the emf induced in the wire,direction of the emf and end of the wire which is at the higher electrical potential are

1.5 \times 10 - 3 V

, East to West, Eastern end.

B. 1.5×10−3V West to East, Eastern end.

1.5 \times 10 - 3 V

, West to East, Western end.

1.6 \times 10 - 3 V

, West to East, Eastern end.

Answer : Option B
Explaination / Solution:

$e = B v l = 0.3 \times 10^{- 4} \times 5 \times 10 = 1.5 \times 10^{- 3} V$

according to lenz's law direction of emf is West to East

Under Graduate Entrance Exams NEET Entrance Exam # Physics Dual Nature of Radiation and Matter Prepare / Learn

Q6. If the voltage across the electrodes of a cathode ray tube is 500 volts then energy gained by the electrons is

A. 6

\times 1 0^{- 17}

B. 7

\times 1 0^{- 17}

C. 8

\times 1 0^{- 17}

D. 9

\times 1 0^{- 17}

Answer : Option C
Explaination / Solution:

energy gained by electron

$K = e V_{0} = 1.6 \times 10^{- 19} \times 500 = 8 \times 10^{- 17} J$

Under Graduate Entrance Exams NEET Entrance Exam # Physics Communication Systems Prepare / Learn

Q7. In ground wave propagation the earth

A. attenuates the radiated signal as a result of energy absorption by it

B. none of these

C. amplifies the radiated signal

D. reflects the waves

Answer : Option A
Explaination / Solution:
No Explaination.

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

Q8.

A particle starts from the origin at t = 0 s with a velocity of 10.0 $\hat{j}$ m/s and moves in the x-y plane with a constant acceleration of ( 8.0 $\hat{i}$ + 2.0 $\hat{j}$ ) m $s^{- 2}$ . At what time is the x- coordinate of the particle 16 m? What is the y-coordinate of the particle at that time?

A. 2.2 s, 22 m

B. 2 s, 24 m

C. 1 s, 14 m

D. 1.5 s, 20 m

Answer : Option B
Explaination / Solution:

u = uxi + uyj = 10j,

ux = 0 and uy = 10 m/s

a = axi + ayj = 8i + 2j,

ax = 8 and ay = 2 m/s2

x = uxt + $\frac{1}{2}$ axt2

=> 16 = $\frac{8 t^{2}}{2}$

t = 2 sec

y = uyt + $\frac{a_{y} t^{2}}{2}$ = 10x2 + $\frac{2 \times 2^{2}}{2}$ = 24 m

Under Graduate Entrance Exams NEET Entrance Exam # Physics Electric Charges and Fields Prepare / Learn

Q9.

A system has two charges

q_{A} = 2.5 \times 1 0^{- 7} C

and

q_{B} = - 2.5 \times 1 0^{- 7} C

located at points A: (0, 0, –15 cm) and B: (0,0, +15 cm), respectively. What are the total charge and electric dipole moment of the system?

A. zero,

5.5 \times 1 0^{- 8} C m

B. zero,

6.5 \times 1 0^{- 8} C m

C. zero,

6.5 \times 1 0^{- 8} C m

D. zero,

6.5 \times 1 0^{- 8} C m

Answer : Option C
Explaination / Solution:

Total charge=

2.5 \times 10^{- 7} - 2.5 \times 10^{- 7} = 0

Dipole moment=

2.5 \times 10^{- 7} \times 30 \times 10^{- 2} = 7.5 \times 10^{- 8} C m

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

Q10. A metal rod that is 4.00 m long and 0.50

c m^{2}

in cross-sectional area is found to stretch 0.20 cm under a tension of 5000 N. What is Young’s modulus for this metal?

A. 2.5

\times

1 0^{10}

B. 2.0

\times

1 0^{10}

C. 2.7

\times

1 0^{10}

D. 2.6

\times

1 0^{10}

Answer : Option B
Explaination / Solution:
No Explaination.

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