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NEET 2021 CODE P2

2021 · 52 questions · First 10 Solutions Free
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Q1 mcq
If E and G respectively denote energy and gravitational constant, then E/G has the dimensions of:
a.
[M^2][L^-2][T^-1]
b.
[M^2][L^-1][T^0] Correct Answer
c.
[M][L^-1][T^-1]
d.
[M][L^0][T^0]
Step-by-Step AI Explanation
Verified Method
Energy E = [ML^2T^-2]. Gravitational constant G = [M^-1L^3T^-2]. Therefore, E/G = [ML^2T^-2] / [M^-1L^3T^-2] = [M^2L^-1T^0].
Q1 mcq
If E and G respectively denote energy and gravitational constant, then E/G has the dimensions of:
a.
[M^2][L^-2][T^-1]
b.
[M^2][L^-1][T^0] Correct Answer
c.
[M][L^-1][T^-1]
d.
[M][L^0][T^0]
Step-by-Step AI Explanation
Verified Method
Energy E = [ML^2T^-2]. Gravitational constant G = [M^-1L^3T^-2]. Therefore, E/G = [ML^2T^-2] / [M^-1L^3T^-2] = [M^2L^-1T^0].
Q2 mcq
An inductor of inductance L, a capacitor of capacitance C and a resistor of resistance R are connected in series to an ac source of potential difference V. Potential difference across L, C and R is 40 V, 10 V and 40 V, respectively. The amplitude of current flowing through LCR series circuit is 10√2 A. The impedance of the circuit is:
a.
5 Ω Correct Answer
b.
4√2 Ω
c.
5√2 Ω
d.
4 Ω
Step-by-Step AI Explanation
Verified Method
VR = 40 V, VL = 40 V, VC = 10 V. Net voltage V = sqrt(VR^2 + (VL - VC)^2) = sqrt(40^2 + (40-10)^2) = sqrt(1600 + 900) = 50 V. Impedance Z = V_rms / I_rms. Given current amplitude I0 = 10√2, so I_rms = 10 A. Z = 50/10 = 5 Ω.
Q2 mcq
An inductor of inductance L, a capacitor of capacitance C and a resistor of resistance R are connected in series to an ac source of potential difference V volts. Potential difference across L, C and R is 40 V, 10 V and 40 V, respectively. The amplitude of current flowing through LCR series circuit is 10√2 A. The impedance of the circuit is:
a.
5 Ω Correct Answer
b.
4√2 Ω
c.
5√2 Ω
d.
4 Ω
Step-by-Step AI Explanation
Verified Method
V_R = 40 V, V_L = 40 V, V_C = 10 V. Net voltage V = sqrt(V_R^2 + (V_L - V_C)^2) = sqrt(40^2 + (30)^2) = 50 V. Peak current I = 10√2 A. Impedance Z = V_rms / I_rms = V_peak / I_peak = 50 / 10 = 5 Ω.
Q3 mcq
A body is executing simple harmonic motion with frequency n, the frequency of its potential energy is:
a.
4n
b.
n
c.
2n Correct Answer
d.
3n
Step-by-Step AI Explanation
Verified Method
Potential energy U = (1/2)k(x_0 sin ωt)^2 = (1/2)k x_0^2 sin^2(ωt) = (1/4)k x_0^2 (1 - cos 2ωt). The frequency of potential energy oscillation is 2ω, which corresponds to 2n.
Q3 mcq
A body is executing simple harmonic motion with frequency 'n', the frequency of its potential energy is:
a.
4n
b.
n
c.
2n Correct Answer
d.
3n
Step-by-Step AI Explanation
Verified Method
In SHM, displacement is x = A sin(ωt). Potential energy U = 1/2 k x^2 = 1/2 k A^2 sin^2(ωt) = 1/4 k A^2 (1 - cos(2ωt)). The frequency of oscillation for potential energy is 2ω, which corresponds to 2n.
Q5 mcq
A nucleus with mass number 240 breaks into two fragments each of mass number 120, the binding energy per nucleon of unfragmented nuclei is 7.6 MeV while that of fragments is 8.5 MeV. The total gain in the Binding Energy in the process is:
a.
216 MeV Correct Answer
b.
0.9 MeV
c.
9.4 MeV
d.
804 MeV
Step-by-Step AI Explanation
Verified Method
Gain = (240 * 8.5) - (240 * 7.6) = 240 * (8.5 - 7.6) = 240 * 0.9 = 216 MeV.
Q6 mcq
A parallel plate capacitor has a uniform electric field E in the space between the plates. If the distance between the plates is d and the area of each plate is A, the energy stored in the capacitor is (ε0 = permittivity of free space):
a.
1/2 ε0 E^2 Ad Correct Answer
b.
1/2 ε0 E^2
c.
ε0 EAd
d.
1/2 ε0 E Ad
Step-by-Step AI Explanation
Verified Method
Energy density = 1/2 ε0 E^2. Total energy = Energy density × Volume = 1/2 ε0 E^2 × (Ad).
Q7 mcq
The number of photons per second on an average emitted by the source of monochromatic light of wavelength 600 nm, when it delivers the power of 3.3 × 10^-3 watt will be (h = 6.6 × 10^-34 Js):
a.
10^15
b.
10^18
c.
10^17
d.
10^16 Correct Answer
Step-by-Step AI Explanation
Verified Method
P = n (hc/λ). n = (Pλ) / (hc) = (3.3 × 10^-3 * 600 × 10^-9) / (6.6 × 10^-34 * 3 × 10^8) = 1.98 × 10^-9 / 1.98 × 10^-25 = 10^16.
Q8 mcq
Polar molecules are the molecules:
a.
having a permanent electric dipole moment. Correct Answer
b.
having zero dipole moment.
c.
acquire a dipole moment only in the presence of electric field due to displacement of charges.
d.
acquire a dipole moment only when magnetic field is absent.
Step-by-Step AI Explanation
Verified Method
By definition, polar molecules are molecules that have a permanent electric dipole moment due to the asymmetric distribution of charge.
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Q9 mcq
The half-life of a radioactive nuclide is 100 hours. The fraction of original activity that will remain after 150 hours would be:
a.
2^(-3/2)
b.
1/2
c.
1/(2√2)
d.
2/3
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Q10 mcq
A capacitor of capacitance C, is connected across an ac source of voltage V, given by V=V0 sinωt. The displacement current between the plates of the capacitor, would then be given by:
a.
I_d = V0 ωC sin ωt
b.
I_d = V0 ωC cos ωt
c.
I_d = (V0/ωC) cos ωt
d.
I_d = (V0/ωC) sin ωt
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Q11 mcq
A screw gauge gives the following readings when used to measure the diameter of a wire: Main scale reading : 0 mm, Circular scale reading : 52 divisions. Given that 1 mm on main scale corresponds to 100 divisions on the circular scale. The diameter of the wire from the above data is:
a.
0.052 cm
b.
0.52 cm
c.
0.026 cm
d.
0.26 cm
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Q13 mcq
In a potentiometer circuit a cell of EMF 1.5 V gives balance point at 36 cm length of wire. If another cell of EMF 2.5 V replaces the first cell, then at what length of the wire, the balance point occurs?
a.
62 cm
b.
60 cm
c.
21.6 cm
d.
64 cm
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Q15 mcq
The effective resistance of a parallel connection that consists of four wires of equal length, equal area of cross-section and same material is 0.25 Ω. What will be the effective resistance if they are connected in series?
a.
4 Ω
b.
0.25 Ω
c.
0.5 Ω
d.
1 Ω
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Q16 mcq
Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine. The losses due to frictional force are 10% of the input energy. How much power is generated by the turbine? (g=10 m/s^2)
a.
7.0 kW
b.
10.2 kW
c.
8.1 kW
d.
12.3 kW
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Q16 mcq
Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine. The losses due to frictional force are 10% of the input energy. How much power is generated by the turbine? (g=10 m/s^2)
a.
7.0 kW
b.
10.2 kW
c.
8.1 kW
d.
12.3 kW
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Q17 mcq
An infinitely long straight conductor carries a current of 5 A. An electron is moving with a speed of 10^5 m/s parallel to the conductor. The perpendicular distance between the electron and the conductor is 20 cm. Calculate the magnitude of the force experienced by the electron.
a.
8×10^-20 N
b.
4×10^-20 N
c.
8π×10^-20 N
d.
4π×10^-20 N
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Q18 mcq
Consider the following statements (A) and (B) and identify the correct answer. (A) A zener diode is connected in reverse bias, when used as a voltage regulator. (B) The potential barrier of p-n junction lies between 0.1 V to 0.3 V.
a.
(A) is incorrect but (B) is correct.
b.
(A) and (B) both are correct.
c.
(A) and (B) both are incorrect.
d.
(A) is correct and (B) is incorrect.
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Q18 mcq
Consider the following statements (A) and (B) and identify the correct answer: (A) A zener diode is connected in reverse bias, when used as a voltage regulator. (B) The potential barrier of p-n junction lies between 0.1 V to 0.3 V.
a.
(A) is incorrect but (B) is correct.
b.
(A) and (B) both are correct.
c.
(A) and (B) both are incorrect.
d.
(A) is correct and (B) is incorrect.
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Q19 mcq
A spring is stretched by 5 cm by a force 10 N. The time period of the oscillations when a mass of 2 kg is suspended by it is:
a.
0.628 s
b.
0.0628 s
c.
6.28 s
d.
3.14 s
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Q20 mcq
The electron concentration in an n-type semiconductor is the same as hole concentration in a p-type semiconductor. An external electric field is applied across each of them. Compare the currents in them.
a.
No current will flow in p-type, current will only flow in n-type.
b.
current in n-type = current in p-type.
c.
current in p-type > current in n-type.
d.
current in n-type > current in p-type.
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Q22 mcq
A convex lens ‘A’ of focal length 20 cm and a concave lens ‘B’ of focal length 5 cm are kept along the same axis with a distance ‘d’ between them. If a parallel beam of light falling on ‘A’ leaves ‘B’ as a parallel beam, then the distance ‘d’ in cm will be:
a.
30
b.
25
c.
15
d.
50
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Q23 mcq
The escape velocity from the Earth’s surface is v. The escape velocity from the surface of another planet having a radius, four times that of Earth and same mass density is:
a.
4 v
b.
v
c.
2 v
d.
3 v
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Q26 mcq
Two charged spherical conductors of radius R1 and R2 are connected by a wire. Then the ratio of surface charge densities of the spheres (σ1/σ2) is:
a.
(R2/R1)^2
b.
R1/R2
c.
R2/R1
d.
(R1/R2)^2
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Q30 mcq
If force [F], acceleration [A] and time [T] are chosen as the fundamental physical quantities. Find the dimensions of energy.
a.
[F] [A^-1] [T]
b.
[F] [A] [T]
c.
[F] [A] [T^2]
d.
[F] [A] [T^-1]
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Q30 mcq
If force [F], acceleration [A] and time [T] are chosen as the fundamental physical quantities. Find the dimensions of energy.
a.
[F] [A^-1] [T]
b.
[F] [A] [T]
c.
[F] [A] [T^2]
d.
[F] [A] [T^-1]
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Q31 mcq
A small block slides down on a smooth inclined plane, starting from rest at time t=0. Let Sn be the distance travelled by the block in the interval t=n-1 to t=n. Then, the ratio Sn / Sn+1 is:
a.
(2n)/(2n-1)
b.
(2n-1)/(2n)
c.
(2n-1)/(2n+1)
d.
(2n+1)/(2n-1)
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Q32 mcq
The velocity of a small ball of mass M and density d, when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is d/2, then the viscous force acting on the ball will be:
a.
2 Mg
b.
Mg/2
c.
Mg
d.
3 Mg/2
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Q32 mcq
The velocity of a small ball of mass M and density d, when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is d/2, then the viscous force acting on the ball will be:
a.
2 Mg
b.
Mg/2
c.
Mg
d.
3 Mg/2
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Q33 mcq
Match Column-I (Physical terms) with Column-II (Mathematical relations) for the flow of current through a metallic conductor.
a.
(A)-(R), (B)-(Q), (C)-(S), (D)-(P)
b.
(A)-(R), (B)-(S), (C)-(P), (D)-(Q)
c.
(A)-(R), (B)-(S), (C)-(Q), (D)-(P)
d.
(A)-(R), (B)-(P), (C)-(S), (D)-(Q)
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Q34 mcq
A radioactive nucleus undergoes spontaneous decay in the sequence: A/Z X -> A-4/Z-2 B -> A-4/Z-3 C -> A-4/Z-2 D. The possible decay particles in the sequence are:
a.
beta-, alpha, beta+
b.
alpha, beta-, beta+
c.
alpha, beta+, beta-
d.
beta+, alpha, beta-
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Q35 mcq
Match Column-I with Column-II and choose the correct match.
a.
(A)-(R), (B)-(Q), (C)-(P), (D)-(S)
b.
(A)-(R), (B)-(P), (C)-(S), (D)-(Q)
c.
(A)-(Q), (B)-(R), (C)-(S), (D)-(P)
d.
(A)-(Q), (B)-(P), (C)-(S), (D)-(R)
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Q37 mcq
From a circular ring of mass M and radius R an arc corresponding to a 90-degree sector is removed. The moment of inertia of the remaining part of the ring about an axis passing through the centre and perpendicular to the plane is K times MR^2. Value of K is:
a.
1/8
b.
3/4
c.
7/8
d.
1/4
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Q39 mcq
A ball of mass 0.15 kg is dropped from a height 10 m, strikes the ground and rebounds to the same height. The magnitude of impulse imparted to the ball is (g=10 m/s^2) nearly:
a.
1.4 kg m/s
b.
0 kg m/s
c.
4.2 kg m/s
d.
2.1 kg m/s
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Q40 mcq
A step down transformer connected to 220 V ac mains is made to operate at 11 V, 44 W lamp. Ignoring power losses, what is the current in the primary circuit?
a.
4 A
b.
0.2 A
c.
0.4 A
d.
2 A
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Q41 mcq
A uniform conducting wire of length 12a and resistance R is wound as a coil: (i) equilateral triangle of side a, (ii) square of side a. Magnetic dipole moments in each case respectively are:
a.
4 Ia^2 and 3 Ia^2
b.
3 Ia^2 and 3 Ia^2
c.
3 Ia^2 and Ia^2
d.
3 Ia^2 and 4 Ia^2
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Q42 mcq
A particle of mass 'm' is projected with a velocity v = kVe (k < 1) from the surface of the earth (Ve = escape velocity). The maximum height above the surface reached by the particle is:
a.
(Rk^2) / (1 - k^2)
b.
R * (k^2 / (1 - k))
c.
R * (k^2 / (1 + k))
d.
(R * k) / (1 + k)
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Q42 mcq
A particle of mass m is projected with velocity v = k Ve (k < 1) from the surface of the earth. The maximum height above the surface reached by the particle is:
a.
Rk^2 / (1-k^2)
b.
R(k^2 / (1-k^2))
c.
R(k^2 / (1+k^2))
d.
R(k / 1+k)
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Q43 mcq
A series LCR circuit containing 5.0 H inductor, 80 µF capacitor and 40 Ω resistor is connected to 230 V ac source. The angular frequencies at which power is half the resonant power are:
a.
42 rad/s and 58 rad/s
b.
25 rad/s and 75 rad/s
c.
50 rad/s and 25 rad/s
d.
46 rad/s and 54 rad/s
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Q43 mcq
A series LCR circuit containing 5.0 H inductor, 80 μF capacitor and 40 Ω resistor is connected to 230 V variable frequency ac source. The angular frequencies of the source at which power transferred to the circuit is half the power at the resonant angular frequency are likely to be:
a.
42 rad/s and 58 rad/s
b.
25 rad/s and 75 rad/s
c.
50 rad/s and 25 rad/s
d.
46 rad/s and 54 rad/s
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Q44 mcq
A particle moving in a circle of radius R with a uniform speed takes a time T to complete one revolution. If this particle were projected with the same speed at an angle θ to the horizontal, the maximum height attained by it equals 4R. The angle of projection, θ, is then given by:
a.
θ = sin^-1 [ (2gT^2 / (π^2 R)) - 1 / 2 ]
b.
θ = cos^-1 [ (gT^2 / (π^2 R)) - 1 / 2 ]
c.
θ = cos^-1 [ (R / (2 * g * T^2)) - π^2 ]
d.
θ = sin^-1 [ (R / (2 * g * T^2)) - π^2 ]
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Q45 mcq
Two conducting circular loops of radii R1 and R2 are placed in the same plane with their centres coinciding. If R1 >> R2, the mutual inductance M between them will be directly proportional to:
a.
R1^2 / R2
b.
R2 / R1
c.
R2^2 / R1
d.
R1^2 / R2^2
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Q46 mcq
Twenty seven drops of same size are charged at 220 V each. They combine to form a bigger drop. Calculate the potential of the bigger drop potential.
a.
1980 V
b.
660 V
c.
1320 V
d.
1520 V
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Q48 mcq
A point object is placed at a distance of 60 cm from a convex lens of focal length 30 cm. If a plane mirror were put perpendicular to the principal axis of the lens and at a distance of 40 cm from it, the final image would be formed at a distance of:
a.
20 cm from the plane mirror, it would be a virtual image.
b.
20 cm from the lens, it would be a real image.
c.
30 cm from the lens, it would be a real image.
d.
30 cm from the plane mirror, it would be a virtual image.
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Q55 mcq
The correct option for the number of body centred unit cells in all 14 types of Bravais lattice unit cells is:
a.
3
b.
7
c.
5
d.
2
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Q57 mcq
Tritium, a radioactive isotope of hydrogen, emits which of the following particles?
a.
Neutron (n)
b.
Beta (β-)
c.
Alpha (α)
d.
Gamma (γ)
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Q62 mcq
A particular station of All India Radio, New Delhi, broadcasts on a frequency of 1,368 kHz (kilohertz). The wavelength of the electromagnetic radiation emitted by the transmitter is : [speed of light, c=3.0×10^8 ms^-1]
a.
21.92 cm
b.
219.3 m
c.
219.2 m
d.
2192 m
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Q64 mcq
The right option for the statement 'Tyndall effect is exhibited by', is:
a.
Urea solution
b.
NaCl solution
c.
Glucose solution
d.
Starch solution
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Q76 mcq
Which one of the following methods can be used to obtain highly pure metal which is liquid at room temperature ?
a.
Zone refining
b.
Electrolysis
c.
Chromatography
d.
Distillation
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Q77 mcq
Right option for the number of tetrahedral and octahedral voids in hexagonal primitive unit cell are :
a.
12, 6
b.
8, 4
c.
6, 12
d.
2, 1
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Q99 mcq
Choose the correct option for the total pressure (in atm.) in a mixture of 4 g O2 and 2 g H2 confined in a total volume of one litre at 0°C is: [Given R=0.082 L atm mol^-1 K^-1, T=273 K]
a.
26.02
b.
2.518
c.
2.602
d.
25.18
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