A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since:
a.
a large aperture contributes to the quality and visibility of the images.
b.
a large area of the objective ensures better light gathering power.
c.
a large aperture provides a better resolution.
d.
all of the above.
Correct Answer
Step-by-Step AI Explanation
Verified Method
In an astronomical telescope, a large aperture objective increases light gathering power (brightness) and improves resolving power. A larger focal length allows for greater magnification.
Q2mcq
A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since:
a.
a large aperture contributes to the quality and visibility of the images.
b.
a large area of the objective ensures better light gathering power.
c.
a large aperture provides a better resolution.
d.
all of the above.
Correct Answer
Step-by-Step AI Explanation
Verified Method
A large aperture increases the light-gathering capacity (brightness) and the resolving power of the telescope, which are essential for viewing distant astronomical objects.
Q4mcq
Column - I gives certain physical terms associated with flow of current through a metallic conductor. Column - II gives some mathematical relations involving electrical quantities. Match Column - I and Column - II with appropriate relations.
Column - I: (A) Drift Velocity, (B) Electrical Resistivity, (C) Relaxation Period, (D) Current Density
Column - II: (P) m/(ne^2ρ), (Q) nev_d, (R) eEτ/m, (S) E/J
a.
(A)-(R), (B)-(Q), (C)-(S), (D)-(P)
b.
(A)-(R), (B)-(S), (C)-(P), (D)-(Q)
Correct Answer
c.
(A)-(R), (B)-(S), (C)-(Q), (D)-(P)
d.
(A)-(R), (B)-(P), (C)-(S), (D)-(Q)
Step-by-Step AI Explanation
Verified Method
Drift velocity v_d = eEτ/m (R). Electrical Resistivity ρ = E/J (S). Relaxation period τ from conductivity formula σ = ne^2τ/m => τ = mσ/(ne^2) = m/(ne^2ρ) (P). Current density J = nev_d (Q).
Q4mcq
Column - I gives certain physical terms associated with flow of current through a metallic conductor. Column - II gives some mathematical relations involving electrical quantities. Match Column - I and Column - II with appropriate relations.
Column - I: (A) Drift Velocity, (B) Electrical Resistivity, (C) Relaxation Period, (D) Current Density
Column - II: (P) m / ne^2τ, (Q) nevd, (R) eEτ / m, (S) E / J
a.
(A)-(R), (B)-(Q), (C)-(S), (D)-(P)
b.
(A)-(R), (B)-(S), (C)-(P), (D)-(Q)
Correct Answer
c.
(A)-(R), (B)-(S), (C)-(Q), (D)-(P)
d.
(A)-(R), (B)-(P), (C)-(S), (D)-(Q)
Step-by-Step AI Explanation
Verified Method
Drift velocity vd = eEτ/m (R). Resistivity ρ = m/(ne^2τ) (P). Relaxation period τ is related through ρ = m/(ne^2τ) or J = σE => ρ = E/J (S). Current density J = nevd (Q). Thus (A)-(R), (B)-(S), (C)-(P), (D)-(Q).
Q6mcq
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: (ε_0 = permittivity of free space)
a.
1/2 ε_0 E^2 Ad
Correct Answer
b.
1/2 ε_0 E^2
c.
ε_0 EAd
d.
ε_0 E^2 Ad
Step-by-Step AI Explanation
Verified Method
Energy density u = (1/2)ε_0 E^2. Total energy U = u * Volume = (1/2)ε_0 E^2 * (A * d).
Q7mcq
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
Polar molecules are those in which the center of positive and negative charges do not coincide, resulting in a permanent electric dipole moment.
Q8mcq
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.
Correct Answer
Step-by-Step AI Explanation
Verified Method
Zener diodes are indeed used in reverse bias for regulation. However, the potential barrier for a Silicon p-n junction is typically ~0.7 V, and for Germanium it is ~0.3 V. Given the range, (B) is generally considered incorrect in the context of standard textbook NEET physics as it omits the dominant Silicon case.
Q11mcq
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
Correct Answer
b.
0.25 Ω
c.
0.5 Ω
d.
1 Ω
Step-by-Step AI Explanation
Verified Method
In parallel, R/4 = 0.25 => R = 1 Ω. In series, R_eq = 4R = 4 * 1 = 4 Ω.
Q12mcq
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
Correct Answer
d.
12.3 kW
Step-by-Step AI Explanation
Verified Method
Input Power = mgh/t = (dm/dt)gh = 15 * 10 * 60 = 9000 W = 9 kW. Output Power = Input * 0.90 = 8.1 kW.
Q13mcq
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
Correct Answer
b.
0.0628 s
c.
6.28 s
d.
3.14 s
Step-by-Step AI Explanation
Verified Method
k = F/x = 10 / 0.05 = 200 N/m. T = 2π√(m/k) = 2π√(2/200) = 2π√(1/100) = 2π/10 = 0.2 * 3.14 = 0.628 s.
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The electron concentration in an n-type semiconductor is the same as hole concentration in a p-type semiconductor. An external field (electric) 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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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
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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
b.
0.9 MeV
c.
9.4 MeV
d.
804 MeV
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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-1)/(2n+1)
b.
(2n+1)/(2n-1)
c.
(2n-1)/(2n)
d.
(2n)/(2n-1)
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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.
Id = V0 ωC sinωt
b.
Id = V0 ωC cosωt
c.
Id = V0/ωC cosωt
d.
Id = V0/ωC sinωt
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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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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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For a plane electromagnetic wave propagating in x-direction, which one of the following combination gives the correct possible directions for electric field (E) and magnetic field (B) respectively ?
a.
-j, +k, -j, +k
b.
+j, +k, -j, +k
c.
-j, +k, -j, -k
d.
+j, -j, -j, +k
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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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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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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.
3Mg/2
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A uniform rod of length 200 cm and mass 500 g is balanced on a wedge placed at 40 cm mark. A mass of 2 kg is suspended from the rod at 20 cm and another unknown mass ‘m’ is suspended from the rod at 160 cm mark. Find the value of ‘m’ such that the rod is in equilibrium. (g=10 m/s^2)
a.
1/12 kg
b.
1/2 kg
c.
1/3 kg
d.
1/6 kg
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From a circular ring of mass ‘M’ and radius ‘R’ an arc corresponding to a 90° sector is removed. The moment of inertia of the remaining part of the ring about an axis passing through the centre of the ring and perpendicular to the plane of the ring is ‘K’ times ‘MR^2’. Then the value of ‘K’ is :
a.
1/8
b.
3/4
c.
7/8
d.
1/4
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A uniform conducting wire of length 12a and resistance ‘R’ is wound up as a current carrying coil in the shape of: (i) an equilateral triangle of side ‘a’. (ii) a square of side ‘a’. The magnetic dipole moments of the coil 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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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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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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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.
R2^2 / R1
b.
R1 / R2^2
c.
R1^2 / R2
d.
R2^2 / R1^2
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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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