Physics - Online Test

Under Graduate Entrance Exams NEET Entrance Exam Physics TEST : 113

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

Q1. Two waves represented by Y1 = a1 sin wt and Y2 = a2 cos wt are superimposed at a point at a particular instant. The amplitude of resultant wave is

A. a21+a22−−−−−−√

B. a1+a2

C. a1−a2

D. a21−a22−−−−−−√

Answer : Option A
Explaination / Solution:
No Explaination.

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

Q2.

In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of

2 .0 \times 1 0^{10}

Hz and amplitude 48 V

m^{- 1}

.wavelength of the wave and amplitude of the oscillating magnetic field are

A. 2.5

\times 1 0^{- 2} m

, 2.6

\times 1 0^{- 7}

B. 1.8

\times 1 0^{- 2} m

, 1.8

\times 1 0^{- 7}

C. 1.5

\times 1 0^{- 2} m

, 1.6

\times 1 0^{- 7}

D. 2.2

\times 1 0^{- 2} m

, 1.6

\times 1 0^{- 7}

Answer : Option C
Explaination / Solution:
No Explaination.

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

Q3. A pair of adjacent coils has a mutual inductance of 1.5 H. If the current in one coil changes from 0 to 20 A in 0.5 s, change of flux linkage with the other coil is

A. 30 Wb .

B. 35 Wb

C. 45 Wb

D. 40 Wb

Answer : Option A
Explaination / Solution:

Δϕ=MΔi=1.5×20=30Wb

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

Q4. If a beam goes undeflected in Thomson’s experiment, then speed of the electron is (given E = 30 V

c m^{- 1}

and

B = 6 x 10-4 T)

A. 6.5

\times 1 0^{6}

m/s

B. 5.5

\times 1 0^{6}

m/s

C. 5

\times 1 0^{6}

m/s

D. 6

\times 1 0^{6}

m/s

Answer : Option C
Explaination / Solution:

If a beam goes undeflected then

$\begin{aligned} F_{E} = F_{M} \\ q E = q v B \\ E = 30 V c m^{- 1} = 30 \times 100 V m^{- 1} \\ B = 6 \times 10^{- 4} T \\ v = \frac{E}{B} = \frac{30 \times 100}{6 \times 10^{- 4}} = 5 \times 10^{- 6} m / s \end{aligned}$

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

Q5. In sky wave propagation the ionosphere

A. reflects the radiated signal

B. none of these

C. transmits the radiated signal

D. absorbs the radiated signal

Answer : Option A
Explaination / Solution:
No Explaination.

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

Q6.

A fighter plane flying horizontally at an altitude of 1.5 km with speed 720 km/h passes directly overhead an anti-aircraft gun. At what angle from the vertical should the gun be fired for the shell with muzzle speed 600 m $s^{- 1}$ to hit the plane? At what minimum altitude should the pilot fly the plane to avoid being hit ? (Take g = 10 m $s^{- 2}$ ).

A. at an angle of 20.5

^{\circ}

with the vertical, 12 km

B. at an angle of 23.5

^{\circ}

with the vertical, 17 km

C. at an angle of 21.5

^{\circ}

with the vertical, 15 km

D. at an angle of 19.5

^{\circ}

with the vertical, 16 km

Answer : Option D
Explaination / Solution:

Height of the fighter plane = 1.5 km = 1500 m
Speed of the fighter plane, v = 720 km/h = 200 m/s
Let θ be the angle with the vertical so that the shell hits the plane. The situation is shown in the given figure.

Muzzle velocity of the gun, u = 600 m/s
Time taken by the shell to hit the plane = t
Horizontal distance travelled by the shell = uxt
Distance travelled by the plane = vt
The shell hits the plane. Hence, these two distances must be equal.
uxt = vt
u Sin θ = v
Sin θ = $\frac{v}{u} = \frac{200}{600}$
θ = Sin-1(0.33) = 19.50

In order to avoid being hit by the shell, the pilot must fly the plane at an altitude (H) higher than the maximum height achieved by the shell.
∴ H = $\frac{u^{2} s i n^{2} (90 - θ)}{2 g} = \frac{(600)^{2} c o s^{2} θ}{2 g}$
= $\frac{360000 \times c o s^{2} (19.5)}{2 \times 10}$
= 16006.482 m
≈ 16 km

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

Q7. Two insulated charged copper spheres A and B have their centres separated by a distance of 50 cm and have identical sizes. A third sphere of the same size but uncharged is brought in contact with the first, then brought in contact with the second, and finally removed from both. What is the new force of repulsion between A and B?

A. 6.7×10−3/N6.7×10−3/N

B. 3.7×10−3/N3.7×10−3/N

C. 5.7×10−3/N

D. 4.7×10−3/N

Answer : Option C
Explaination / Solution:

If A and B having charge

6.5 \times 10^{- 7} C

each and a third sphere C having charge=0 If C is in contact with A than new charge on A and C

q_{A} = q_{C} = \frac{6.5 \times 10^{- 7} + 0}{2} = 3.25 \times 10^{- 7} C

Now C is put in contact with B so new charge on C and B

Now new charge on A is

q_{A} = 3.25 \times 10^{- 7} C

and on B is

q_{B} = 4.875 \times 10^{- 7} C

and distance =50 cm So

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

Q8.

In constructing a large mobile, an artist hangs an aluminum sphere of mass 6.0 kg from a vertical steel wire 0.50 m long and 2.5

\times

1 0^{- 3}

c m^{2}

in cross-sectional area. On the bottom of the sphere he attaches a similar steel wire, from which he hangs a brass cube of mass 10.0 kg. Compute the elongation.

A. 1.4 mm upper, 1.0 mm lower

B. 1.5 mm upper, 1.1 mm lower

C. 1.7 mm upper, 1.0 mm lower

D. 1.6 mm upper, 1.0 mm lower

Answer : Option D
Explaination / Solution:
No Explaination.

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

Q9. A refrigerator is to maintain eatables kept inside at 9

^{\circ}

C. If room temperature is 36

^{\circ}

C, calculate the coefficient of performance.

A. 11.8

B. 11.4

C. 12.4

D. 10.4

Answer : Option D
Explaination / Solution:

K=TLTH−TL=282309−282=10.4

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

Q10. The radius of the innermost electron orbit of a hydrogen atom is 5.3×10–11 m. What are the radii of the n = 2 and n =3 orbits?

A. 2.32

\times 1 0^{- 10}

m; 4.37

\times 1 0^{- 10}

B. 2.12

\times 1 0^{- 10}

m; 4.77

\times 1 0^{- 10}

C. 2.22

\times 1 0^{- 10}

m; 4.27

\times 1 0^{- 10}

D. 2.42

\times 1 0^{- 10}

m; 4.47

\times 1 0^{- 10}

Answer : Option B
Explaination / Solution:
No Explaination.

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Under Graduate Entrance Exams NEET Entrance Exam Physics TEST : 113