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

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

Q1. The wiring for a refrigerator contains a starter capacitor. A voltage of amplitude 170 V and frequency 60.0 Hz applied across the capacitor is to produce a current amplitude of 0.850 A through the capacitor. Capacitance required is

A. 23.4 μF

B. 13.3 μF

C. 17.8 μF

D. 15.3 μF

Answer : Option B
Explaination / Solution:

$\begin{aligned} V = 170 v o l t \\ f = 60 H z \\ i = 0.85 A \\ V = i X_{C} = i \frac{1}{ω C} = \frac{i}{2 π f C} \end{aligned}$

Capacitance required

$C = \frac{i}{2 π f V} = \frac{0.85}{2 \times 3.14 \times 60 \times 170} = 13.3 \times 10^{- 6} F = 13.3 μ F$

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

Q2. A potentiometer wire, 10 m long, has resistance 40 ohms. It is put in series with a resistance 760 ohms and connected to a 2 volt battery. The potential gradient in the wire is :

A. 1×10−2volt/m

B. 1×10−6volt/m

C. 1×10−3volt/m

D. 1×10−4volt/m

Answer : Option A
Explaination / Solution:

The total resistance is the sum of the resistance of the potentiometer and the external resistance. $R = R_{p o t} + R_{e x t} = 40 + 760 = 800 Ω$

Current through the potentiometer is

$\begin{array}{l} I = \frac{E}{R} = \frac{2}{800} \\ I = 2.5 \times 10^{- 3} A \end{array}$

The potential drop across the potentiometer

$\begin{array}{l} V = I \times R_{p o t} \\ V = (2.5 \times 10^{- 3}) \times 40 \\ \Rightarrow V = 0.1 V \end{array}$

The potential gradient = ( potential drop across the potentiometer)/ length of the potentiometer wire)

$\begin{array}{l} = \frac{0.1}{10} V / m \\ ∴ P o t e n t i a l g r a d i e n t = 1 \times 10^{- 2} V / m \end{array}$

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

Q3. If the length of a simple pendulum is increases by 1percent, then the new time-period

A. Increases by 2.0 percent

B. Increases by 1 percent

C. Increases by 0.5 percent

D. Decreases by 0.5 percent

Answer : Option B
Explaination / Solution:
No Explaination.

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

Q4. For what distance is ray optics a good approximation when the aperture is 3 mm wide and the wavelength is 500 nm?

A. 16 m

B. 17 m

C. 18 m

D. 15 m

Answer : Option C
Explaination / Solution:
No Explaination.

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

Q5. A cylinder of iron is placed so that it is free to rotate around its axis. Initially the cylinder is at rest, and a magnetic field is applied to the cylinder so that it is magnetized in a direction parallel to its axis. If the direction of the external field is suddenly reversed, the direction of magnetization will also reverse and the cylinder will begin rotating around its axis because

A. Conservation of mass

B. Conservation of energy

C. Conservation of parity

D. Conservation of angular momentum and spin angular momentum is of the same nature as the angular momentum of rotating bodies

Answer : Option D
Explaination / Solution:
No Explaination.

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

Q6. A bar magnet is equivalent to

A. solenoid carrying current

B. toroid carrying current

C. circular coil carrying current

D. straight conductor carrying current

Answer : Option A
Explaination / Solution:

A solenoid carrying current produces a magnetic field very similar to that of bar magnet. The magnetic field lines emerge from the ends of a solenoid and the number of field lines near its perpendicular bisector is almost equal to zero. A circular coil produces field along its axis. A straight conductor produces a magnetic field that can be represented by concentric circles. A toroid is a solenoid that has collapsed on itself. The field in a toroid is confined to the ring like region bounded by the toroid.

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

Q7. To provide the abundance of holes the impurity added should be

A. monovalent

B. tetravalent

C. trivalent

D. pentavalent

Answer : Option C
Explaination / Solution:

If We introduce a "Trivalent" (3-electron) impurity into the crystalline structure, such as Aluminium, Boron or Indium, which have only three valence electrons available in their outermost orbital, the fourth closed bond cannot be formed. Therefore, a complete connection is not possible, giving the semiconductor material an abundance of positively charged carriers known as "holes" in the structure of the crystal where electrons are effectively missing

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

Q8. A jet lands on an aircraft carrier at 60 m/s. What is its acceleration if it stops in 2.0 s?

A. -10

m s^{- 2}

-30

m s^{- 2}

B. -20

m s^{- 2}

C. 30

m s^{- 2}

D. -10

m s^{- 2}

Answer : Option A
Explaination / Solution:

Initial velocity u = 60 m/s

As it stops then final velocity v = 0 m/s

Time taken t = 2.0 s

We know,

v-u = at

=> 0-60= 2a

=> a = $\frac{- 60}{2} = - 30 m / s^{2}$

-ve sign shows velocity is decreasing.

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

Q9. If a star emitting orange light moves away from the earth, its color will

A. turns gradually blue

B. appear yellow

C. appear red

D. remain the same

Answer : Option C
Explaination / Solution:
No Explaination.

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

Q10.

It is desired to measure the magnitude of field between the poles of a powerful loud speaker magnet. A small flat search coil of area 2 $c m^{2}$ with 25 closely wound turns, is positioned normal to the field direction, and then quickly snatched out of the field region. Equivalently, one can give it a quick $9 0^{\circ}$ turn to bring its plane parallel to the field direction). The total charge flown in the coil (measured by a ballistic galvanometer connected to coil) is 7.5 mC. The combined resistance of the coil and the galvanometer is $0. 50 Ω$ . Field strength of magnet is

A. 0.85 T

B. 0.90 T

C. 0.65 T

D. 0.75 T .

Answer : Option D
Explaination / Solution:

$\begin{aligned} i = \frac{d q}{d t} = \frac{e}{R} \\ | e | = \frac{d ϕ}{d t} = \frac{(d N B A)}{d t} \end{aligned}$

$\begin{aligned} q = \frac{N B A}{R} \\ B = \frac{q R}{N A} = \frac{7.5 \times 10^{- 3} \times 0.5}{25 \times 2 \times 10^{- 4}} = 0.75 T \end{aligned}$

Physics - Online Test

Physics | Online Objective Test | Start Test

Prepare Before Start Test | Learn

UPSC Civil services Entrance exams | Online Test

GATE Exam | Online Test

Under Graduate Entrance Exams | Online Test

Problem Solving and Reasoning | Online Test

CAT Entrance Exams | Online Test

CLAT LAW Entrance exams | Online Test

Banking Entrance exams | Online Test

UGC NET Entrance exams | Online Test

TANCET Anna University | Online Test

TN State Board | Online Test