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Bihar Board Class 12 Science Physics · Ch 4: Moving Charges and Magnetism

Bihar Board Class 12 Science Physics · Ch 4: Moving Charges and Magnetism is an online chapter test in the Bihar Board Class 12 Science pattern, covering Moving Charges and Magnetism. Attempt it on SeatBeat with a timer like the real exam, then see a detailed solution for every question and your score and weak-topic analysis.

30
Questions
20
Minutes
30
Marks
None
Negative marking
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Topics in this test

TopicQuestions
Moving Charges and Magnetism30

Difficulty: 7 medium · 23 hard

Moving Charges and Magnetism MCQ questions with answers

The first 3 of 30 questions. Unlock the series for the rest, each with a solution.

  1. Q1. A galvanometer of resistance $100\,\Omega$ shows full-scale deflection for a current of $1\,\text{mA}$. To convert it into an ammeter of range $1\,\text{A}$, the shunt resistance required is nearly:

    $100\,\Omega$ प्रतिरोध का एक धारामापी $1\,\text{mA}$ की धारा के लिए पूर्ण-स्केल विक्षेप दर्शाता है। इसे $1\,\text{A}$ परिसर के अमीटर में परिवर्तित करने के लिए, आवश्यक शंट प्रतिरोध लगभग है:

    • A. $0.1\,\Omega$ in series / $0.1\,\Omega$ श्रेणीक्रम में
    • B. $0.1\,\Omega$ in parallel / $0.1\,\Omega$ समांतरक्रम में
    • C. $100\,\Omega$ in parallel / $100\,\Omega$ समांतरक्रम में
    • D. $900\,\Omega$ in series / $900\,\Omega$ श्रेणीक्रम में
    Solution

    The shunt is $S=\frac{I_g G}{I-I_g}=\frac{0.001\times100}{1-0.001}=\frac{0.1}{0.999}\approx0.1\,\Omega$, connected in parallel with the galvanometer.

    शंट $S=\frac{I_g G}{I-I_g}=\frac{0.001\times100}{1-0.001}=\frac{0.1}{0.999}\approx0.1\,\Omega$ है, जो धारामापी के समांतर जोड़ा जाता है।

  2. Q2. Consider the following statements about the magnetic force on a moving charge: (i) The magnetic force does no work on the moving charge. (ii) A charge moving parallel to the magnetic field experiences maximum force. (iii) The magnetic force is always perpendicular to the velocity of the charge. Which of the statements are correct?

    गतिमान आवेश पर चुंबकीय बल के विषय में निम्नलिखित कथनों पर विचार करें: (i) चुंबकीय बल गतिमान आवेश पर कोई कार्य नहीं करता है। (ii) चुंबकीय क्षेत्र के समांतर गतिमान आवेश अधिकतम बल अनुभव करता है। (iii) चुंबकीय बल सदैव आवेश के वेग के लंबवत होता है। कौन-से कथन सही हैं?

    • A. (i) and (iii) only / केवल (i) तथा (iii)
    • B. (i), (ii) and (iii) / (i), (ii) तथा (iii)
    • C. (ii) and (iii) only / केवल (ii) तथा (iii)
    • D. (i) and (ii) only / केवल (i) तथा (ii)
    Solution

    Force $\vec{F}=q\vec{v}\times\vec{B}$ is always perpendicular to $\vec{v}$, so it does no work; a charge moving parallel to $\vec{B}$ has $\sin0^\circ=0$, giving zero force, so (ii) is wrong.

    बल $\vec{F}=q\vec{v}\times\vec{B}$ सदैव $\vec{v}$ के लंबवत होता है, अतः यह कोई कार्य नहीं करता; $\vec{B}$ के समांतर गतिमान आवेश के लिए $\sin0^\circ=0$ होता है, जिससे बल शून्य हो जाता है, अतः (ii) गलत है।

  3. Q3. A beam of charged particles passes undeviated through a region where a uniform electric field $E=3\times10^{5}\,\text{V m}^{-1}$ and a uniform magnetic field $B=0.1\,\text{T}$ act perpendicular to each other (a velocity selector). The speed of the selected particles is:

    आवेशित कणों का एक पुंज एक ऐसे क्षेत्र से बिना विचलित हुए गुजरता है जहाँ एक समान विद्युत क्षेत्र $E=3\times10^{5}\,\text{V m}^{-1}$ तथा एक समान चुंबकीय क्षेत्र $B=0.1\,\text{T}$ परस्पर लंबवत कार्य करते हैं (एक वेग वरणकर्ता)। चयनित कणों की चाल है:

    • A. $3\times10^{4}\,\text{m s}^{-1}$
    • B. $0.3\times10^{5}\,\text{m s}^{-1}$
    • C. $3\times10^{7}\,\text{m s}^{-1}$
    • D. $3\times10^{6}\,\text{m s}^{-1}$
    Solution

    For no deflection the electric and magnetic forces balance, so $qE=qvB$, giving $v=\frac{E}{B}=\frac{3\times10^{5}}{0.1}=3\times10^{6}\,\text{m s}^{-1}$.

    कोई विचलन न होने के लिए विद्युत तथा चुंबकीय बल संतुलित होते हैं, अतः $qE=qvB$, जिससे $v=\frac{E}{B}=\frac{3\times10^{5}}{0.1}=3\times10^{6}\,\text{m s}^{-1}$ प्राप्त होता है।

Frequently asked questions

How many questions are in the Bihar Board Class 12 Science Physics · Ch 4: Moving Charges and Magnetism?

30 questions for 30 marks, to be answered in 20 minutes.

Is there negative marking in the Bihar Board Class 12 Science Physics · Ch 4: Moving Charges and Magnetism?

No — wrong answers are not penalised in this test.

Which topics does the Bihar Board Class 12 Science Physics · Ch 4: Moving Charges and Magnetism cover?

Moving Charges and Magnetism (30 questions).

Is the Bihar Board Class 12 Science Physics · Ch 4: Moving Charges and Magnetism free?

It is part of the BSEB Class 12 Science Test Series 2027 — Chapter-wise + Full Tests (41 tests, ₹149). You can first try Hindi · Ch 1: Chandradhar Sharma Guleri for free.

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