Bihar Board Class 12th Physics Answer Key 2025: The answer key for the Class 12th Physics exam 2025, conducted by the Bihar School Examination Board (BSEB), will be released soon. This answer key will help students compare their answers and estimate their total marks. Once the answer key is released, students can match their answers with the correct ones and evaluate their performance in the exam. This process helps students understand areas where they need improvement and where they performed well. Using the answer key allows students to learn from their mistakes and improve their preparation for future exams.
Check: Bihar Board 12th Physics Exam Analysis 2025
Importance of Bihar Board Class 12th Physics Answer Key 2025:
- Check Your Answers – The answer key helps you compare your answers with the correct ones to see how well you performed in the exam.
- Estimate Your Marks – By adding marks for correct answers and checking mistakes, you can get an idea of your expected score before the official results are out.
- Reduce Exam Stress – Knowing your expected marks in advance can help you stay calm while waiting for the final results.
Check: BSEB Class 12 Physics Question Paper 2025
Bihar Board Class 12th Physics Answer Key 2025: Key Highlights
Feature | Answer Key |
| Exam Date: | February 5, 2025, from 9:30 AM to 12:45 PM |
| Board Name: | Bihar School Examination Board (BSEB) |
| Question Paper Format: | Multiple Choice Questions (MCQs), Short Answer Questions And Long Answer Questions |
BSEB Bihar Board Class 12 Physics Answer Key 2025
(Set-D Solutions)
SECTION - A
Objective Type Questions
1. Two equal positive point charges of 1 μC charge are kept at a distance of 1 metre in air. The electric potential energy of the system will be
(A) 1 joule
(B) 1 eV
(C) 9×10-3 joule
(d) zero
Answer: (C) 9×10-3 joule
2. Which one of the following is a unit of capacity?
(A) Coulomb
(B) ampere
(C) volt
(D) coulomb/volt
Answer: (D) coulomb/volt
3. The capacity of any condenser does not depend upon
(A) shape of plates
(B) size of plates
(C) charge on plates
(D) distance between plates
Answer: (C) charge on plates
4. The electric field on the outer surface of a charged conductor is
(A)parallel to the surface
(B) perpendicular to the surface
(C)at 45° angle to the surface
(D)zero
Answer: (B) Perpendicular to the surface
5. If a conductor is placed in an external electric field, the field inside the conductor will be
(A)zero
(B)equal to the external field
(C)twice the external field
(D)half the external field
Answer: (A) Zero
6. Which of the following statements is true for two-point charges of opposite sign P
(A) The potential energy is always negative
(B) The potential energy is always positive
(C) The potential energy can be either positive or negative
(D) The potential energy is zero
Answer: (A) The potential energy is always negative
7. Gauss's law states that the electric flux through a closed surface is
(A) proportional to the charge enclosed
(B) inversely proportional to the charge enclosed
(C)zero
(D) proportional to the square of the charge enclosed
Answer: (A) Proportional to the charge enclosed
8. Kilowatt-hour (kWh) is the unit of
(A) energy
(B) power
(C) torque
(D) force
Answer: (A) Energy
9. Which of the following laws is based on the principle of energy conservation?
(A) Ampere's law
(B) Faraday's law of electrolysis
(C) Lenz's law
(D) None of these
Answer: (C) Lenz's law
10. When an ammeter is shunted then its measurement limit
(A) increases
(B) decreases
(C) remains unchanged
(D) none of these
Answer: (A) Increases
11. The dimensional formula of permeability is
(A) [MLT-2A-2]
(B) [MLT2A-2]
(C) [MLT2 A2]
(D) [MLT-2A]
Answer: (A) [MLT-2A-2]
12. Unit of √(μ0/ε0) is
(A) newton/coulomb
(B) ohm
(C) henry
(D) farad
Answer: (C) Henry
13. If the number of turns is increased in any moving coil
galvanometer, then its sensitivity
(A) increases
(B)decreases.
(C) remains unchanged
(D)may increase or may decrease
Answer: (A) increases
14. At neutral points
(A) B> B
(B) B<BH
(C) B=BH
(D) B=0
(B intensity of the magnetic field of the magnet; By horizontal component of the magnetic field of the earth)
Answer: (D) B = 0
15. The peak value of an alternating current is 10 A. Its root mean the square value will be
(A) 5 A
(B) 7:07 A
(C)10 A
(D) 14:14 A
Answer: (B) 7:07 A
16. In a purely inductive circuit, the power factor is
(A) O
(B) 1
(C) 0.5
(D) infinity
Answer: (A) O
17. In an a.c. circuit containing only a capacitor, the phase difference between current and voltage is
(A) 0°
(B) 90°
(C) 180"
(D)45°
Answer: (B) 90°
18. In resonance condition, the frequency of the L-C circuit is
(A) 1/2π√1/LC
(B)2π√1/LC
(C)2π√LC
(D) 1/2π√LC
Answer: (B) 2π√(1/LC)
19. In a step-up transformer, the value of current in the secondary coil compared to the primary coil is
(A) equal
(B)less
(C) more
(D)no relation between the two
Answer: (B) less
20. The image formed by a convex mirror is always
(A) in between the centre of curvature and focus
(B) in between the centre of curvature and infinity
(C) in between pole and focus
(D)none of these
Answer: (C) in between pole and focus
21. If the critical angle for total internal reflection from any medium to vacuum is 30°, then the velocity of light in the medium is
(A) 3x108 m/sec
(B) 1.5×108 m/sec
(C) 6x108 m/sec
(D) 4.5×108 m/sec
Answer: (B) 1.5×108 m/sec
22. The distance between two charges is made half and one of the charges is also halved. The force acting between the two will become as compared to the previous value
(A) half
(B) double
(C) thrice
(D) none of these
Answer: (A) half
23. The speed of an electron accelerated from rest under a potential difference V is
(A) proportional to V
(B) proportional to √V
(C) proportional to 1/V
(D) proportional to V2
Answer: (B) proportional to √V
24. The specific charge of an electron is
(A) 1.8×10-19 C/kg
(B) 1.67×10-19 C/kg
(C) 1.8×1011 c/kg
(D) 6.67x1011 C/kg
Answer: (C) 1.8×10^11 C/kg
27. The distance between two equal and opposite charges of 0.2 μC is 3.0 cm. Their electric dipole moment will be
(A) 6.0 coulomb-metre
(B) 6-0x10-8 coulomb-metre
(C) 12.0 coulomb-metre
(D) 12.0x10-8 coulomb-metre
Answer: (B) 6.0×10^-8 coulomb-metre
28. Inside a closed surface n electric dipoles are situated. The total electric flux coming out from the closed surface will be
(A)q/ε0
(C)nq/ε0
(B)2q/ε0
(D)zero
Answer: (D) zero
29. Two light waves of equal amplitude and equal wavelengths are superimposed. The amplitude of the resultant wave will be maximum when the phase difference between them is
(A) zero
(B) π/4
(C) π/2
(D) π
Answer: (A) zero
30. In polarised light the angle between the plane of vibration and the plane of polarization is
(A) 0°
(C) 90°
(B) 45°
(D) 180°
Answer: (C) 90°
(Set-C Solutions)
1. A capacitor of 100 uF is charged to 100 volts. The energy stored in it
will be
(A)0.5 joule
(B)5 joule
(C)50 joule
(D) 100 joule
Answer : (A)0.5 joule
2. Which of the following has unit volt-metre -1?
(A) Electric flux
(B)Electric potential
(C) Electric field
(D)Electric Capacity
Answer : (A) Electric flux
3. The relation between drift velocity v of free electrons in a conductor in electric conduction and potential difference V between ends of the conductor is
(A) proportional to V
(B)inversely proportional to V
(C)proportional to v2
(D) inversely proportional to v2
Answer : (A) proportional to V
4. The graph between voltage V of a conductor and current I is a straight line, which makes an angle with a y-axis (which represents I). The resistance of the conductor will be
(A)tan θ
(B)cot θ
(C)sin θ
(D)cos θ
Answer : (A) tan θ
5. The power of the electric circuit is
(A) V.R
(B) V2.R
(C)v2/R
(D)v2.R.I
Answer: (C)v2/R
6. With the rise in temperature, the resistance of semiconductors
(A) increases
(B) decreases
(C)sometimes increases and sometimes decreases
(D)remains unchanged
Answer: (B) decreases
7. What is the main difference between isotopes of the same element?
(A) Number of protons
(B)Number of neutrons
(C)Number of electrons
(D)Atomic number
Answer: (B) Number of neutrons
8. Which series of hydrogen spectrum lies in the visible portion?
(A) Lyman series
(B)Balmer series
(C) Paschen series
(D)Brackett series
Answer: (B)Balmer series
Steps To Download Bihar Board Class 12th Physics Answer Key?
- Step 1: Visit the official website of the Bihar Board, biharboardonline.bihar.gov.in.
- Step 2: Click on the "Answer Key" or "उत्तर कुंजी" section on the homepage.
- Step 3: Select the "Intermediate PhysicsScience Answer Key 2025" link.
- Step 4: Download the answer key in PDF format and compare it with your answers.
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