Magnetisation & Magnetic Intensity — MH-CET Physics MCQs with Solutions
Free MH-CET Physics Magnetisation & Magnetic Intensity MCQs with step-by-step solutions (21 questions). Part of Magnetic Materials. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Magnetisation & Magnetic Intensity · easy · theory
The intensity of magnetisation of a material is defined as:
A. The pole strength per unit area
B. The magnetic moment per unit volume ✓ Correct
C. The flux per unit area
D. The magnetic moment per unit mass
Solution: Its SI unit is $\text{A}/\text{m}$, the same as that of magnetic intensity $H$.
Q2 — Magnetisation & Magnetic Intensity · easy · theory
The SI unit of magnetic intensity $H$ is:
A. $\text{A}\cdot\text{m}$
B. $\text{A}/\text{m}$ ✓ Correct
C. $\text{Wb}$
D. $\text{T}$
Solution: $H$ describes the magnetising field produced by free currents, independent of the material's response.
Q3 — Magnetisation & Magnetic Intensity · medium · theory
The relation between magnetic induction $B$, magnetic intensity $H$ and magnetisation $M$ is:
A. $B = \mu_0(H - M)$
B. $B = \mu_0HM$
C. $B = \mu_0(H + M)$ ✓ Correct
D. $B = \dfrac{\mu_0H}{M}$
Solution: The total induction combines the applied magnetising field and the contribution of the aligned dipoles of the material.
Q4 — Magnetisation & Magnetic Intensity · medium · theory
Magnetic susceptibility is defined as:
A. $\chi = \dfrac{B}{H}$
B. $\chi = \dfrac{H}{M}$, measured in $\text{A}/\text{m}$
C. $\chi = \dfrac{M}{H}$, a dimensionless quantity ✓ Correct
D. $\chi = \mu_0 M H$
Solution: Since $M$ and $H$ share the same unit, their ratio is a pure number that measures how readily a material magnetises.
Q5 — Magnetisation & Magnetic Intensity · easy · theory
The magnetic permeability of a material is defined as:
A. $\mu = \dfrac{H}{B}$
B. $\mu = \dfrac{B}{H}$ ✓ Correct
C. $\mu = BH$
D. $\mu = \dfrac{M}{H}$
Solution: It measures how much magnetic induction a given magnetising field produces in the material.
Q6 — Magnetisation & Magnetic Intensity · medium · theory
The relative permeability $\mu_r$ and the susceptibility $\chi$ are related by:
A. $\mu_r = \chi - 1$
B. $\mu_r = \dfrac{1}{\chi}$
C. $\mu_r = \chi$
D. $\mu_r = 1 + \chi$ ✓ Correct
Solution: This follows directly from $B = \mu_0(H + M) = \mu_0H(1 + \chi)$.
Q7 — Magnetisation & Magnetic Intensity · easy · theory
For a diamagnetic material, the magnetic susceptibility is:
A. Large and positive
B. Small and positive
C. Small and negative ✓ Correct
D. Exactly zero
Solution: The induced magnetisation opposes the applied field, so $M$ and $H$ have opposite signs.
Q8 — Magnetisation & Magnetic Intensity · medium · theory
The SI units of magnetic induction $B$ and magnetic intensity $H$ are respectively:
A. $\text{A}/\text{m}$ and tesla
B. Tesla and weber
C. Tesla and $\text{A}/\text{m}$ ✓ Correct
D. Weber and tesla
Solution: These are different physical quantities: $B$ is the total induction, $H$ the magnetising field.
Q9 — Magnetisation & Magnetic Intensity · easy · theory
Magnetic flux through a surface of area $A$ placed perpendicular to a field $B$ is:
A. $BA$, measured in weber ✓ Correct
B. $BA$, measured in tesla
C. $\dfrac{A}{B}$, measured in weber
D. $\dfrac{B}{A}$, measured in tesla
Solution: One weber is one tesla square metre; flux is a scalar quantity.
Q10 — Magnetisation & Magnetic Intensity · easy · numerical
A material has magnetic susceptibility $999$. Its relative permeability is:
A. $998$
B. $999$
C. $1$
D. $1000$ ✓ Correct
Solution: $\mu_r = 1 + \chi = 1 + 999 = 1000$.
Q11 — Magnetisation & Magnetic Intensity · easy · numerical
A material has relative permeability $5000$. Its magnetic susceptibility is:
A. $5001$
B. $0.0002$
C. $4999$ ✓ Correct
D. $5000$
Solution: $\chi = \mu_r - 1 = 5000 - 1 = 4999$.
Q12 — Magnetisation & Magnetic Intensity · medium · numerical
A specimen of volume $10^{-4}\text{ m}^3$ has a magnetic moment of $2\text{ A}\cdot\text{m}^2$. Its intensity of magnetisation is:
A. $5 \times 10^{-5}\text{ A}/\text{m}$
B. $2 \times 10^2\text{ A}/\text{m}$
C. $2 \times 10^4\text{ A}/\text{m}$ ✓ Correct
D. $2 \times 10^{-4}\text{ A}/\text{m}$
Solution: $M = \dfrac{\text{magnetic moment}}{\text{volume}} = \dfrac{2}{10^{-4}} = 2 \times 10^4\text{ A}/\text{m}$.
Q13 — Magnetisation & Magnetic Intensity · hard · numerical
In vacuum, a magnetic intensity of $1000\text{ A}/\text{m}$ produces an induction of:
A. $1.26 \times 10^{-6}\text{ T}$
B. $1.26 \times 10^{-3}\text{ T}$ ✓ Correct
C. $1000\text{ T}$
D. $4\pi \times 10^{-7}\text{ T}$
Solution: In vacuum $M = 0$, so $B = \mu_0H = 4\pi \times 10^{-7} \times 1000 \approx 1.26 \times 10^{-3}\text{ T}$.
Q14 — Magnetisation & Magnetic Intensity · medium · numerical
A magnetising field of $1000\text{ A}/\text{m}$ produces an induction of $0.5\text{ T}$ in a material. Its permeability is:
A. $2000\text{ T}\cdot\text{m}/\text{A}$
B. $5 \times 10^{-4}\text{ T}\cdot\text{m}/\text{A}$ ✓ Correct
C. $5 \times 10^{-4}\text{ A}/\text{m}$
D. $500\text{ T}\cdot\text{m}/\text{A}$
Solution: $\mu = \dfrac{B}{H} = \dfrac{0.5}{1000} = 5 \times 10^{-4}\text{ T}\cdot\text{m}/\text{A}$.
Q15 — Magnetisation & Magnetic Intensity · hard · numerical
A material has permeability $5 \times 10^{-4}\text{ T}\cdot\text{m}/\text{A}$. Its relative permeability is approximately:
A. $3980$
B. $398$ ✓ Correct
C. $628$
D. $40$
Solution: $\mu_r = \dfrac{\mu}{\mu_0} = \dfrac{5 \times 10^{-4}}{1.26 \times 10^{-6}} \approx 398$.
Q16 — Magnetisation & Magnetic Intensity · medium · numerical
A magnetising field of $100\text{ A}/\text{m}$ produces a magnetisation of $3000\text{ A}/\text{m}$. The susceptibility is:
A. $30$ ✓ Correct
B. $3000$
C. $0.033$
D. $3100$
Solution: $\chi = \dfrac{M}{H} = \dfrac{3000}{100} = 30$.
Q17 — Magnetisation & Magnetic Intensity · easy · numerical
A field of $0.2\text{ T}$ passes normally through an area of $0.05\text{ m}^2$. The magnetic flux is:
A. $0.25\text{ Wb}$
B. $0.1\text{ Wb}$
C. $0.01\text{ Wb}$ ✓ Correct
D. $4\text{ Wb}$
Solution: $\Phi = BA = 0.2 \times 0.05 = 0.01\text{ Wb}$.
Q18 — Magnetisation & Magnetic Intensity · medium · numerical
A magnet of volume $10^{-5}\text{ m}^3$ has an intensity of magnetisation of $10^6\text{ A}/\text{m}$. Its magnetic moment is:
A. $10\text{ A}\cdot\text{m}^2$ ✓ Correct
B. $10^{11}\text{ A}\cdot\text{m}^2$
C. $0.1\text{ A}\cdot\text{m}^2$
D. $10^{-11}\text{ A}\cdot\text{m}^2$
Solution: Magnetic moment $= M \times V = 10^6 \times 10^{-5} = 10\text{ A}\cdot\text{m}^2$.
Q19 — Magnetisation & Magnetic Intensity · medium · numerical
A diamagnetic material has susceptibility $-10^{-5}$. Its relative permeability is:
A. $-10^{-5}$
B. $0.99999$ ✓ Correct
C. $1.00001$
D. $10^5$
Solution: $\mu_r = 1 + \chi = 1 - 10^{-5} = 0.99999$, just less than unity as expected for a diamagnet.
Q20 — Magnetisation & Magnetic Intensity · medium · numerical
In vacuum, an induction of $1.26 \times 10^{-3}\text{ T}$ corresponds to a magnetic intensity of:
A. $1.26 \times 10^{-3}\text{ A}/\text{m}$
B. $1000\text{ A}/\text{m}$ ✓ Correct
C. $10^6\text{ A}/\text{m}$
D. $100\text{ A}/\text{m}$
Solution: $H = \dfrac{B}{\mu_0} = \dfrac{1.26 \times 10^{-3}}{1.26 \times 10^{-6}} = 1000\text{ A}/\text{m}$.
Q21 — Magnetisation & Magnetic Intensity · medium · numerical
The magnetic susceptibility and relative permeability of vacuum are respectively:
A. $1$ and $1$
B. $1$ and $0$
C. $0$ and $0$
D. $0$ and $1$ ✓ Correct
Solution: Vacuum cannot be magnetised, so $\chi = 0$ and $\mu_r = 1 + 0 = 1$.