A mixture of N2 and Ar gases in a cylinder contains 7 g of N2 and 8 g of Ar. If the total pressure of the mixture of the gases in the cylinder is 27 bar, the partial pressure of N2 is : [Use atomic masses (in g mol–1) : N = 14, Ar = 40]
a.
9 bar
b.
12 bar
c.
15 bar
Correct Answer
d.
18 bar
Step-by-Step AI Explanation
Verified Method
Moles of N2 = 7/28 = 0.25 mol. Moles of Ar = 8/40 = 0.2 mol. Mole fraction of N2 = 0.25 / (0.25 + 0.2) = 0.25 / 0.45 = 5/9. Partial pressure = mole fraction * total pressure = (5/9) * 27 = 15 bar.
Q11mcq
A mixture of N2 and Ar gases in a cylinder contains 7 g of N2 and 8 g of Ar. If the total pressure of the mixture of the gases in the cylinder is 27 bar, the partial pressure of N2 is : [Use atomic masses (in g mol–1) : N = 14, Ar = 40]
a.
9 bar
b.
12 bar
c.
15 bar
Correct Answer
d.
18 bar
Step-by-Step AI Explanation
Verified Method
Moles of N2 = 7/28 = 0.25. Moles of Ar = 8/40 = 0.2. Total moles = 0.45. Mole fraction of N2 = 0.25 / 0.45 = 5/9. Partial pressure of N2 = (5/9) * 27 = 15 bar.
Q12mcq
An element has a body centered cubic (bcc) structure with a cell edge of 288 pm. The atomic radius is
a.
(√3/4) * 288 pm
Correct Answer
b.
(√2/4) * 288 pm
c.
(4/√3) * 288 pm
d.
(4/√2) * 288 pm
Step-by-Step AI Explanation
Verified Method
For a bcc structure, the relation between atomic radius (r) and edge length (a) is r = (√3/4) * a. Given a = 288 pm.
Q12mcq
An element has a body centered cubic (bcc) structure with a cell edge of 288 pm. The atomic radius is
a.
(sqrt(3)/4) * 288 pm
Correct Answer
b.
(sqrt(2)/4) * 288 pm
c.
(4/sqrt(3)) * 288 pm
d.
(4/sqrt(2)) * 288 pm
Step-by-Step AI Explanation
Verified Method
For BCC structure, the relationship between radius r and edge length 'a' is 4r = a * sqrt(3), so r = (sqrt(3)/4) * a.
Q46mcq
Light with an average flux of 20 W/cm2 falls on a non-reflecting surface at normal incidence having surface area 20 cm2. The energy received by the surface during time span of 1 minute is :
a.
10 × 10^3 J
b.
12 × 10^3 J
c.
24 × 10^3 J
Correct Answer
d.
48 × 10^3 J
Step-by-Step AI Explanation
Verified Method
Power = Flux × Area = 20 W/cm^2 × 20 cm^2 = 400 W. Energy = Power × Time = 400 J/s × 60 s = 24000 J = 24 × 10^3 J.
Q46mcq
Light with an average flux of 20 W/cm^2 falls on a non-reflecting surface at normal incidence having surface area 20 cm^2. The energy received by the surface during time span of 1 minute is:
a.
10 × 10^3 J
b.
12 × 10^3 J
c.
24 × 10^3 J
Correct Answer
d.
48 × 10^3 J
Step-by-Step AI Explanation
Verified Method
Energy = Intensity × Area × Time = (20 W/cm^2) × (20 cm^2) × (60 s) = 400 × 60 = 24,000 J = 24 × 10^3 J.
Q47mcq
For transistor action, which of the following statements is correct?
a.
Base, emitter and collector regions should have same doping concentrations.
b.
Base, emitter and collector regions should have same size.
c.
Both emitter junction as well as the collector junction are forward biased.
d.
The base region must be very thin and lightly doped.
Correct Answer
Step-by-Step AI Explanation
Verified Method
For effective transistor action, the base is designed to be very thin and lightly doped to minimize recombination of charge carriers.
Q49mcq
In a certain region of space with volume 0.2 m^3, the electric potential is found to be 5 V throughout. The magnitude of electric field in this region is:
a.
zero
Correct Answer
b.
0.5 N/C
c.
1 N/C
d.
5 N/C
Step-by-Step AI Explanation
Verified Method
Electric field E = -dV/dr. Since the potential V is constant (5 V) everywhere, the gradient dV/dr is zero.
Q51mcq
A 40 μF capacitor is connected to a 200 V, 50 Hz ac supply. The rms value of the current in the circuit is, nearly :
An iron rod of susceptibility 599 is subjected to a magnetising field of 1200 A m^-1. The permeability of the material of the rod is : (μ0 = 4π × 10^-7 T m A^-1)
a.
2.4π × 10^-4 T m A^-1
b.
8.0 × 10^-5 T m A^-1
c.
2.4π × 10^-5 T m A^-1
d.
2.4π × 10^-7 T m A^-1
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A short electric dipole has a dipole moment of 16 × 10^-9 C m. The electric potential due to the dipole at a point at a distance of 0.6 m from the centre of the dipole, situated on a line making an angle of 60° with the dipole axis is :
a.
50 V
b.
200 V
c.
400 V
d.
zero
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Light of frequency 1.5 times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?
a.
doubled
b.
four times
c.
one-fourth
d.
zero
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A series LCR circuit is connected to an ac voltage source. When L is removed from the circuit, the phase difference between current and voltage is π/3. If instead C is removed from the circuit, the phase difference is again π/3 between current and voltage. The power factor of the circuit is:
a.
zero
b.
0.5
c.
1.0
d.
-1.0
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A series LCR circuit is connected to an ac voltage source. When L is removed from the circuit, the phase difference between current and voltage is π/3. If instead C is removed from the circuit, the phase difference is again π/3 between current and voltage. The power factor of the circuit is :
a.
zero
b.
0.5
c.
1.0
d.
–1.0
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A spherical conductor of radius 10 cm has a charge of 3.2 × 10^-7 C distributed uniformly. What is the magnitude of electric field at a point 15 cm from the centre of the sphere?
a.
1.28 × 10^4 N/C
b.
1.28 × 10^5 N/C
c.
1.28 × 10^6 N/C
d.
1.28 × 10^7 N/C
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A spherical conductor of radius 10 cm has a charge of 3.2 × 10⁻⁷ C distributed uniformly. What is the magnitude of electric field at a point 15 cm from the centre of the sphere? (1/(4πε₀) = 9 × 10⁹ Nm²C⁻²)
a.
1.28 × 10⁴ N/C
b.
1.28 × 10⁵ N/C
c.
1.28 × 10⁶ N/C
d.
1.28 × 10⁷ N/C
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A ray is incident at an angle of incidence i on one surface of a small angle prism (with angle of prism A) and emerges normally from the opposite surface. If the refractive index of the material of the prism is μ, then the angle of incidence is nearly equal to:
a.
A/2μ
b.
2A/μ
c.
μA
d.
A/2μ
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A resistance wire connected in the left gap of a metre bridge balances a 10 Ω resistance in the right gap at a point which divides the bridge wire in the ratio 3 : 2. If the length of the resistance wire is 1.5 m, then the length of 1 Ω of the resistance wire is:
a.
1.0 × 10⁻² m
b.
1.0 × 10⁻¹ m
c.
1.5 × 10⁻¹ m
d.
1.5 × 10⁻² m
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A capillary tube of radius r is immersed in water and water rises in it to a height h. The mass of the water in the capillary is 5 g. Another capillary tube of radius 2r is immersed in water. The mass of water that will rise in this tube is:
a.
2.5 g
b.
5.0 g
c.
10.0 g
d.
20.0 g
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In Young’s double slit experiment, if the separation between coherent sources is halved and the distance of the screen from the coherent sources is doubled, then the fringe width becomes:
a.
double
b.
half
c.
four times
d.
one-fourth
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A ball is thrown vertically downward with a velocity of 20 m/s from the top of a tower. It hits the ground after some time with a velocity of 80 m/s. The height of the tower is:
a.
360 m
b.
340 m
c.
320 m
d.
300 m
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Two particles of mass 5 kg and 10 kg respectively are attached to the two ends of a rigid rod of length 1 m with negligible mass. The centre of mass of the system from the 5 kg particle is nearly at a distance of :
a.
33 cm
b.
50 cm
c.
67 cm
d.
80 cm
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Two particles of mass 5 kg and 10 kg respectively are attached to the two ends of a rigid rod of length 1 m with negligible mass. The centre of mass of the system from the 5 kg particle is nearly at a distance of:
a.
33 cm
b.
50 cm
c.
67 cm
d.
80 cm
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In a guitar, two strings A and B made of same material are slightly out of tune and produce beats of frequency 6 Hz. When tension in B is slightly decreased, the beat frequency increases to 7 Hz. If the frequency of A is 530 Hz, the original frequency of B will be:
a.
523 Hz
b.
524 Hz
c.
536 Hz
d.
537 Hz
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In a guitar, two strings A and B made of same material are slightly out of tune and produce beats of frequency 6 Hz. When tension in B is slightly decreased, the beat frequency increases to 7 Hz. If the frequency of A is 530 Hz, the original frequency of B will be:
a.
523 Hz
b.
524 Hz
c.
536 Hz
d.
537 Hz
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Two cylinders A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stop cock is suddenly opened. The process is :
a.
isothermal
b.
adiabatic
c.
isochoric
d.
isobaric
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The capacitance of a parallel plate capacitor with air as medium is 6 μF. With the introduction of a dielectric medium, the capacitance becomes 30 μF. The permittivity of the medium is : (ε0 = 8.85 × 10^–12 C^2 N^–1 m^–2)
a.
0.44 × 10^–13 C^2 N^–1 m^–2
b.
1.77 × 10^–12 C^2 N^–1 m^–2
c.
0.44 × 10^–10 C^2 N^–1 m^–2
d.
5.00 C^2 N^–1 m^–2
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An electron is accelerated from rest through a potential difference of V volt. If the de Broglie wavelength of the electron is 1.227 × 10^–2 nm, the potential difference is :
a.
10 V
b.
10^2 V
c.
10^3 V
d.
10^4 V
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A wire of length L, area of cross section A is hanging from a fixed support. The length of the wire changes to L1 when mass M is suspended from its free end. The expression for Young’s modulus is :
a.
MgL / AL1
b.
Mg(L1 - L) / AL
c.
MgL / AL
d.
MgL / A(L1 - L)
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Two bodies of mass 4 kg and 6 kg are tied to the ends of a massless string. The string passes over a pulley which is frictionless. The acceleration of the system in terms of acceleration due to gravity (g) is :
a.
g
b.
g/2
c.
g/5
d.
g/10
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