Question: Q. 8. The vertical component of Earth’s magnetic field at a place is $\sqrt{3}$ times the horizontal component. What is the value of angle of dip at this place?
R [OD 2012]
Sol. We know that
Vertical component of Earth’s magnetic field,
$$ B_{v}=B \sin \theta $$
Horizontal component of Earth’s magnetic filed,
$\begin{aligned} & H=B \cos \theta \ & \text { Where } \theta \text { is the angle of dip }\end{aligned}$
$1 / 2$
According to the question, at a place
$$ \frac{B_{v}}{H}=\sqrt{3} $$
$1 / 2$
$\Rightarrow$ B $\frac{B \sin \theta}{B \cos \theta}=\sqrt{3}$
$$ \begin{align*} \tan \theta & =\sqrt{3} \ \theta & =60^{\circ} \end{align*} $$
Q.9. Give two points to distinguish between a paramagnetic and a diamagnetic substance.
R [Foreign 2014]
(Any two) $1+1$
Q. 10. The susceptibility of a magnetic material is $-2.6 \times 10^{5}$. Identify the type of magnetic material and state its two properties.
R [Delhi I, II, III 2012]
Show Answer
Solution:
Ans. Diamagnetic material.
Properties :
(i) They have the tendency to move from stronger to weaker part of the external magnetic field.
(ii) They expel magnetic field lines.
(iii) Such substances are repelled by a bar magnet. (iv) When placed in an external magnetic field, a net magnetic dipole moment is developed inside it which is in a direction opposite to that of the applied magnetic field.
(Any two) $1 / 2+1 / 2$
[CBSE Marking Scheme 2012]
