JAC 12th Science Physics Answer key 2025: Check correct Answers

JAC 12th Science Physics Answer key 2025: Check correct Answers: Great to Announce that our Jharkhand Academic Council Ranchi (JAC Board) has conducting its board examination of class 12th Science Physics i.e. of Intermediate standard. The subject is Physics which held on 20th of February 2025.

The subject covered up almost of 30 objective questions (MCQs) and some Subjective questions. And students had to answer only 22 subjective questions out of which only 16 needed to attempt as per of their convenience. Students of Arts can match their answer key of their subjects which they already appeared for the exam, and from this website, they also be able to know how many questions they have attempted to correct by matching their answer keys from Jharkhandlab.com.

JAC 12th Science Physics Answer key 2025

Jharkhand Academic Council (JAC) has examinee the board level exam in Subject Physics of Intermediate Standard science the subject were conducted on 21th of February 2025. The examination was held in second shift from afternoon 2:00 pm to 5:15 pm. The total of 80 marks questions were asked in which total of about 52 questions in number and students had to answer those on their own words. All questions were compulsory to answer for the better Grade.

There is about 52 questions and from number 1 to 25 were multiple choice questions (MCQs) containing 4 options and has to choose the most appropriate option among them and each correct answer containing 1 marks. And from 31 to 38 were short answer types on which only 6 questions were compulsory to answer and each question contained 2 marks, along with it, from question number 39 to 46 were again short type question of 3 marks each and answering 6 is compulsory. With it, from 47 to 52 were the most important long type questions and its number were total of about 5 marks for each question, and has to attend only 4.

The remaining 30 marks will based on Internal assignments that are provided to the Students through their colleges.

Name of Organization	Jharkhand Academic Council, Ranchi
Category	Answer Key
Class	12th, Science
Question Type	Objective & Subjective
Exam Date	21th February 2025
Subject	Physics
Exam Shift	2nd Sitting
Exam Timing	2:00 pm to 5:15 pm
Total Marks	80 Marks(Written)
Official Website	https://jac.jharkhand.gov.in
Telegram	Join Us

JAC 12th Science Physics Answer key 2025

Question Number	Physics Answer Key (Option Number)
Question Number- 01	A
Question Number- 02	B
Question Number- 03	C
Question Number- 04	C
Question Number- 05	A
Question Number- 06	C
Question Number- 07	A
Question Number- 08	D
Question Number- 09	D
Question Number- 10	D
Question Number- 11	C
Question Number- 12	C
Question Number- 13	C
Question Number- 14	A
Question Number- 15	B
Question Number- 16	B
Question Number- 17	C
Question Number- 18	B
Question Number- 19	D
Question Number- 20	C
Question Number- 21	D
Question Number- 22	D
Question Number- 23	B
Question Number- 24	B
Question Number- 25	A

Objective type questions asked in your board exams

All these questions were asked by Jharkhand Academic Council Ranchi (JAC Board) of Subject Physics of class 12th Science in the board examination of 2025, The questions and their answers are given here:

MCQs:

1. How many electrons will have a charge of one Coulomb?

कितने इलेक्ट्रॉनों का आवेश एक कूलॉम होगा?
(A) 6.25×10186.25 \times 10^{18}6.25×1018
(B) 6×25×10196 \times 25 \times 10^{19}6×25×1019
(C) 5×25×10185 \times 25 \times 10^{18}5×25×1018
(D) 5×25×10195 \times 25 \times 10^{19}5×25×1019

✅ Answer / उत्तर: (A) 6.25×10186.25 \times 10^{18}6.25×1018

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2. An electron placed in an electric field experiences an electrical force equal to its weight. The magnitude of the field is

विद्युत क्षेत्र में रखा गया इलेक्ट्रॉन अपने भार के बराबर विद्युत बल का अनुभव करता है। क्षेत्र का परिमाण है
(A) mgemgemge
(B) mg/emg/emg/e
(C) e/mge/mge/mg
(D) e2g/2me^2g/2me2g/2m

✅ Answer / उत्तर: (B) mg/emg/emg/e

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3. Two charges +1C+1C+1C and −1C-1C−1C are placed 1 m apart. The potential at the center of the line joining the two charges will be

दो आवेश +1C+1C+1C तथा −1C-1C−1C को 1 मीटर की दूरी पर रखा गया है। दोनों आवेशों को मिलाने वाली रेखा के केंद्र पर विभव होगा
(A) 2V2V2V
(B) −2V-2V−2V
(C) 000
(D) 0.5V0.5V0.5V

✅ Answer / उत्तर: (C) 000

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4. Three capacitors each having capacitance CCC are connected in series. Their equivalent capacitance is

तीन संधारित्र जिनमें प्रत्येक की धारिता CCC है, श्रेणीक्रम में जुड़े हैं। उनकी तुल्य धारिता है
(A) 3C3C3C
(B) 3/C3/C3/C
(C) C/3C/3C/3
(D) 1/3C1/3C1/3C

✅ Answer / उत्तर: (C) C/3C/3C/3

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5. A 100-watt electric bulb is connected to a 220-volt electric source. The resistance of the bulb’s filament is

100 वाट के विद्युत बल्ब को 220 वोल्ट के विद्युत स्रोत से जोड़ा गया है। बल्ब के तंतु का प्रतिरोध है
(A) 484 Ω484\ \Omega484 Ω
(B) 100 Ω100\ \Omega100 Ω
(C) 22000 Ω22000\ \Omega22000 Ω
(D) 242 Ω242\ \Omega242 Ω

✅ Answer / उत्तर: (A) 484 Ω484\ \Omega484 Ω

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6. The algebraic sum of all the currents at any point in an electrical circuit is

विद्युतीय परिपथ के किसी बिंदु पर सभी धाराओं का बीजीय योग होता है
(A) धनात्मक (Positive)
(B) ऋणात्मक (Negative)
(C) शून्य (Zero)
(D) अनंत (Infinite)

✅ Answer / उत्तर: (C) शून्य (Zero)

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7. A 5T magnetic field would be equal to

एक 5T5T5T वाला चुम्बकीय क्षेत्र बराबर होगा
(A) 5Wb/m25Wb/m^25Wb/m2
(B) 5×105Wb/m25 \times 10^5 Wb/m^25×105Wb/m2
(C) 5×102Wb/m25 \times 10^2 Wb/m^25×102Wb/m2
(D) 5×102N/A−m5 \times 10^2 N/A – m5×102N/A−m

✅ Answer / उत्तर: (A) 5Wb/m25Wb/m^25Wb/m2

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8. A uniform magnetic field is produced

एक समान चुम्बकीय क्षेत्र उत्पन्न होता है
(A) सीधे धारावाही चालक से (From a straight current-carrying conductor)
(B) धारावाही वृत्तीय लूप के केंद्र पर (At the center of a current-carrying circular loop)
(C) धारावाही वृत्ताकार लूप की धुरी पर (At the axis of a current-carrying circular loop)
(D) धारावाही परिनालिका के अंदर (Inside a current-carrying solenoid)

✅ Answer / उत्तर: (D) धारावाही परिनालिका के अंदर (Inside a current-carrying solenoid)

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9. The value of magnetic induction at a distance rrr from a single pole is inversely proportional to

किसी एकल ध्रुव से दूरी rrr पर चुम्बकीय प्रेरण का मान व्युत्क्रमानुपाती होता है
(A) rrr
(B) r2r^2r2
(C) 1/r1/r1/r
(D) 1/r21/r^21/r2

✅ Answer / उत्तर: (D) 1/r21/r^21/r2

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10. A bar magnet of magnetic moment MMM is placed in a uniform magnetic field of intensity BBB at an angle θ\thetaθ with its direction. The torque applied on it is

चुम्बकीय आघूर्ण MMM के एक छड़-चुम्बक को तीव्रता BBB के एकसमान चुम्बकीय क्षेत्र में उसकी दिशा से θ\thetaθ कोण बनाते हुए रखा गया है। उस पर लगने वाला बलाघूर्ण है
(A) MBMBMB
(B) MBcos⁡θMB \cos\thetaMBcosθ
(C) MB(1−cos⁡θ)MB (1 – \cos\theta)MB(1−cosθ)
(D) MBsin⁡θMB \sin\thetaMBsinθ

✅ Answer / उत्तर: (D) MBsin⁡θMB \sin\thetaMBsinθ

11. The unit of mutual inductance is

अन्योन्य प्रेरकत्व का मात्रक है
(A) Weber (वेबर)
(B) Ohm (ओम)
(C) Henry (हेनरी)
(D) Gauss (गॉस)

✅ Answer / उत्तर: (C) Henry (हेनरी)

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12. A conductor of length lll is moving with velocity vvv parallel to a magnetic field of intensity BBB. The induced e.m.f. in the conductor will be

लम्बाई lll का एक चालक तीव्रता BBB के चुम्बकीय क्षेत्र के समानांतर vvv वेग से घूम रहा है। चालक में प्रेरित वि.वा.बल होगा
(A) lvBlvBlvB
(B) 12lvB\frac{1}{2} lvB21​lvB
(C) 000
(D) 12l2vB\frac{1}{2} l^2 vB21​l2vB

✅ Answer / उत्तर: (C) 000

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13. If the peak value of alternating voltage in a circuit is E0E_0E0​, then the root mean square value will be

यदि किसी परिपथ में प्रत्यावर्ती वोल्टता का शिखर मान E0E_0E0​ हो, तो वर्ग माध्य मूल का मान होगा
(A) E02\frac{E_0}{2}2E0​​
(B) E0E_0E0​
(C) E02\frac{E_0}{\sqrt{2}}2​E0​​
(D) E022\frac{E_0^2}{2}2E02​​

✅ Answer / उत्तर: (C) E02\frac{E_0}{\sqrt{2}}2​E0​​

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14. The unit of reactance is

प्रतिघात का मात्रक है
(A) Ohm (ओम)
(B) Mho (म्हो)
(C) Farad (फैराड)
(D) Ampere (ऐम्पियर)

✅ Answer / उत्तर: (A) Ohm (ओम)

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15. The frequency of microwaves is

माइक्रो-तरंगों की आवृत्ति होती है
(A) Less than the frequency of radio waves (रेडियो तरंगों की आवृत्ति से कम)
(B) More than the frequency of radio waves (रेडियो तरंगों की आवृत्ति से अधिक)
(C) More than the frequency of visible waves (दृश्य तरंगों की आवृत्ति से अधिक)
(D) More than the frequency of infrared rays (अवरक्त किरणों की आवृत्ति से अधिक)

✅ Answer / उत्तर: (B) More than the frequency of radio waves (रेडियो तरंगों की आवृत्ति से अधिक)

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16. The speed of electromagnetic waves in vacuum is given by the equation

निर्वात में विद्युतचुंबकीय तरंगों की गति निम्नलिखित समीकरण से दी जाती है
(A) c=μ0ε0c = \mu_0 \varepsilon_0c=μ0​ε0​
(B) c=1/μ0ε0c = 1/\sqrt{\mu_0 \varepsilon_0}c=1/μ0​ε0​​
(C) c=VEc = VEc=VE
(D) c=μ0c = \mu_0c=μ0​

✅ Answer / उत्तर: (B) c=1/μ0ε0c = 1/\sqrt{\mu_0 \varepsilon_0}c=1/μ0​ε0​​

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17. The bottom of the pond appears to be slightly elevated because of

तालाब की तली कुछ ऊपर उठी हुई प्रतीत होती है, इसका कारण है
(A) Interference of light (प्रकाश का व्यतिकरण)
(B) Reflection of light (प्रकाश का परावर्तन)
(C) Refraction of light (प्रकाश का अपवर्तन)
(D) Diffraction of light (प्रकाश का विवर्तन)

✅ Answer / उत्तर: (C) Refraction of light (प्रकाश का अपवर्तन)

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18. If the focal length of a lens is fff meter, then the value of its power will be

यदि किसी लेंस की फोकस दूरी fff मीटर हो, तो इसकी क्षमता का मान होगा
(A) fff diopter
(B) 1f\frac{1}{f}f1​ diopter
(C) (1−f)(1 – f)(1−f) diopter
(D) 100f100f100f diopter

✅ Answer / उत्तर: (B) 1f\frac{1}{f}f1​ diopter

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19. According to Huygens, light waves are

हाइगेन्स के अनुसार प्रकाश की तरंगें होती हैं
(A) Mechanical, longitudinal (यांत्रिक, अनुदैर्ध्य)
(B) Mechanical, transverse (यांत्रिक, अनुप्रस्थ)
(C) Electromagnetic (विद्युत-चुम्बकीय)
(D) Mechanical, spherical (यांत्रिक, गोलीय)

✅ Answer / उत्तर: (D) Mechanical, spherical (यांत्रिक, गोलीय)

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20. Two waves whose intensity ratio is 9:1 produce interference. The ratio of maximum and minimum intensities will be

दो तरंगे जिनकी तीव्रताओं का अनुपात 9:1 है, व्यतिकरण उत्पन्न करती हैं। अधिकतम तथा न्यूनतम तीव्रताओं का अनुपात होगा
(A) 10:8
(B) 9:1
(C) 4:1
(D) 2:1

✅ Answer / उत्तर: (C) 4:1

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21. The energy of a photon with wavelength λ\lambdaλ is

तरंगदैर्ध्य λ\lambdaλ वाले फोटॉन की ऊर्जा होती है
(A) h/λh/\lambdah/λ
(B) hλh \lambdahλ
(C) hλ/ch \lambda / chλ/c
(D) hc/λhc / \lambdahc/λ

✅ Answer / उत्तर: (D) hc/λhc / \lambdahc/λ

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22. The radius of Bohr’s second orbit for hydrogen is

हाइड्रोजन के लिए बोर की द्वितीय कक्षा की त्रिज्या है
(A) rrr
(B) r/2r/2r/2
(C) 2r2r2r
(D) 4r4r4r

✅ Answer / उत्तर: (D) 4r4r4r

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23. The nuclei have their mass numbers in the ratio of 1:3. The ratio of their nuclear densities would be

दो नाभिकों की द्रव्यमान संख्याओं का अनुपात 1:3 है। उनके नाभिकीय घनत्वों का अनुपात होगा
(A) (3)1/3:1(3)^{1/3}:1(3)1/3:1
(B) 1:11:11:1
(C) 1:31:31:3
(D) 3:13:13:1

✅ Answer / उत्तर: (B) 1:11:11:1

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24. The conduction band is partially empty in

चालन बैंड आंशिक रूप से रिक्त होता है
(A) Non-conductors (अचालक)
(B) Semi-conductors (अर्धचालक)
(C) Metals (धातु)
(D) Super-conductors (अतिचालक)

✅ Answer / उत्तर: (B) Semi-conductors (अर्धचालक)

25. Silicon is a semiconductor. By adding a small amount of arsenic to it, its conductivity

सिलिकॉन एक अर्धचालक है। इसमें आर्सेनिक की थोड़ी मात्रा मिलाने से इसकी चालकता
(A) Will increase (बढ़ जाएगी)
(B) Will decrease (घट जाएगी)
(C) Will remain unchanged (अपरिवर्तित रहेगी)
(D) Will become zero (शून्य हो जाएगी)

✅ Answer / उत्तर: (A) Will increase (बढ़ जाएगी)

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