816 + Interview Questions in MAGNETISM IN GENERAL AWARENESS Page 17 InterviewSolution

801.	Two tangent galvanometer P and Q are connected in series and a current is passed through them . Radii of coils of P and Q are in the ratio 4:3 while their number of turns are in ratio 4:9 . If the galvanometer P shows a deflection of `30^(@)` , find the deflection shown by Q.
Answer» Correct Answer - `60^(@)`

Discussion

802.	A tangent galvanometer has two circular coils having turns in the ratio 1:10 . When the coil with smaller number of turns is used,a current of 0.5A produces a deflection of `45^(@)` . What will be the reduction factor of the galvanometer when the coil with larger number of turns is used?
Answer» Correct Answer - 0.05 A

Discussion

803.	A bar magnet has a pole strength of 15 Am. If the distance from its centre of either of the poles is 15 cm, arrange the following steps in sequential order to find its magnetic moment in SI unit. (a) Write the given value of pole strength (m) of the magnet. (b) Substitute the value in the above formula to get the value of M. (c) Find the value of length (l) of the magnet from the problem and convert it into SI unit. (d) Write the required formula, i.e., magnetic moment (M)=mx 2lA. acbdB. cabdC. adcbD. dbac
Answer» Correct Answer - C (a) Write the given value of pole strength (m ) of the magnet. (b) Write the required formula, ie magnetic moment (M) =m x 2l (c) Find the value of (l) of the magnet from the problem and convert it into SI unit. (d) Substitute the values in the above formula to get the value of M.

Discussion

804.	The time period of a vibration magnetometer is `T_(0)`. Its magnet is replaced by another magnet whose moment of inertia is 3 times and magnetic moment is `1//3` of the initial magnet. The time period now willA. `3T_(0)`B. `T_(0)`C. `(T_(0))/(sqrt3)`D. `(T_(0))/(3)`
Answer» Correct Answer - A `Tpropsqrt((I)/(M))`

Discussion

805.	The time period of a vibration magnetometer is `T_(0)`. Its magnet is replaced by another magnet whose moment of inertia is 3 times and magnetic moment is `1//3` of the initial magnet. The time period now willA. `3T`.B. `T`.C. `T_(0)//sqrt(3)`D. `T//3`
Answer» Correct Answer - A

Discussion

806.	The perio of oscillation of a magnet in vibration magnetometer is 2 sec. The period of oscillation of a magnet whosr magnetic moment is four times that of the first magnet isA. 1 secB. 4 secC. 8 secD. 0.5 sec
Answer» Correct Answer - A

Discussion

807.	The error in measuring the curent with tangent galvanometer is minimum when the deflection is aboutA. `odot`B. `30dot`C. `45dot`D. `60dot`
Answer» Correct Answer - C

Discussion

808.	The period of oscillation of a vibration magnetometer depends on which of the following factors? where I is the moment of inertia of the magnet about the axis of suspension, M is the magnetic moment of the magnet and H is the external magnetic fieldA. I and M onlyB. M and onlyC. I and H onlyD. I , M and H only whereI is the moment of inertia of the magnet about the axis of suspension, M is the magnetic moment of the magnet and H is the external magnetic field
Answer» Correct Answer - D

Discussion

809.	In a tangent galvanometer a current of `0.1 A` produces a deflection of `30^(@)`. The current required to produce a deflection of `60^(@)` isA. `0.2 A`B. `0.3 A`C. `0.4 A`D. `0.5 A`
Answer» Correct Answer - B

Discussion

810.	A tangent galvanometer has a reduction factor of 0. 2A . It gives a deflection of `45^(@)` when connected to a bettery of 6 V having internal resistance of `15 Omega` . Find the galvanometer resistance.
Answer» Correct Answer - `15 Omega`

Discussion

811.	A bar magnet has magnetic moment 3.6 Am2 and pole strength 10.8 Am. Determine its magnetic length and geometric length.
Answer» Given: m = 3.6 Am², q_m = 10.8 Am To find: i. Magnetic length ii. Geometric length Formulae: i. Magnetic length = \(\frac{m}{q_m}\) ii. Geometric length = \(\frac{6}{5}\) × magnetic length. Calculation: From formula (i), Magnetic length = \(\frac{3.6}{10.8}\) = 0.33 m From formula (ii), Geometric length = \(\frac{6}{5}\) × 0.33 = 0.396 m ≈ 0.4 m

811.

A bar magnet has magnetic moment 3.6 Am2 and pole strength 10.8 Am. Determine its magnetic length and geometric length.

Answer»

Given: m = 3.6 Am², q_m = 10.8 Am

To find:

i. Magnetic length

ii. Geometric length

Formulae:

i. Magnetic length = \(\frac{m}{q_m}\)

ii. Geometric length = \(\frac{6}{5}\) × magnetic length.

Calculation: From formula (i),

Magnetic length = \(\frac{3.6}{10.8}\) = 0.33 m

From formula (ii),

Geometric length = \(\frac{6}{5}\) × 0.33

= 0.396 m ≈ 0.4 m

Discussion

812.	Two tangent galvanometers P and Q connected in series . The number of turns in P is four times than of Q. When a current is passed through them P shows a deflection of `60^(@)` and Q shows a deflection of `30^(@)`. What is ratio of the radii of the coils of the two tangent galvanometers ?
Answer» Correct Answer - `4:3`

Discussion

813.	A current of 10 A produces a deflection of `45^(@)` in a tangent galvanometer. What is the value of the current which will produce a deflection of `30^(@)` in the same galvanometer?
Answer» Correct Answer - 5.77 A

Discussion

814.	The period of oscillations of a magnet is 2 sec. When it is remagnetised so that the pole strength is 4 times its period will beA. 4 secB. 2 secC. 1 secD. `1//2 sec`
Answer» Correct Answer - C

Discussion

815.	The bob of a simple pendulim is replaced by a magnet. The oscillations are set along the length of the magnet. A copper coil is added so that one pole of the magnet passes in and out of coil. The coil is sort-circuited. Then which one of the following happens?A. Period decreasesB. Period does not changeC. Oscillations are dampedD. Amplitude increases
Answer» Correct Answer - C

Discussion

816.	At a certain place a magnet makes 30 oscillations per minute. At another place where the magnetic field is double, its time period will beA. 4 secB. 2 secC. `(1)/(2)sec`D. `sqrt(2) sec`
Answer» Correct Answer - D

Discussion

Explore topic-wise InterviewSolutions in .

Two tangent galvanometer P and Q are connected in series and a current is passed through them . Radii of coils of P and Q are in the ratio 4:3 while their number of turns are in ratio 4:9 . If the galvanometer P shows a deflection of `30^(@)` , find the deflection shown by Q.

A tangent galvanometer has two circular coils having turns in the ratio 1:10 . When the coil with smaller number of turns is used,a current of 0.5A produces a deflection of `45^(@)` . What will be the reduction factor of the galvanometer when the coil with larger number of turns is used?

The time period of a vibration magnetometer is `T_(0)`. Its magnet is replaced by another magnet whose moment of inertia is 3 times and magnetic moment is `1//3` of the initial magnet. The time period now willA. `3T_(0)`B. `T_(0)`C. `(T_(0))/(sqrt3)`D. `(T_(0))/(3)`

The time period of a vibration magnetometer is `T_(0)`. Its magnet is replaced by another magnet whose moment of inertia is 3 times and magnetic moment is `1//3` of the initial magnet. The time period now willA. `3T`.B. `T`.C. `T_(0)//sqrt(3)`D. `T//3`

The perio of oscillation of a magnet in vibration magnetometer is 2 sec. The period of oscillation of a magnet whosr magnetic moment is four times that of the first magnet isA. 1 secB. 4 secC. 8 secD. 0.5 sec

The error in measuring the curent with tangent galvanometer is minimum when the deflection is aboutA. `odot`B. `30dot`C. `45dot`D. `60dot`

In a tangent galvanometer a current of `0.1 A` produces a deflection of `30^(@)`. The current required to produce a deflection of `60^(@)` isA. `0.2 A`B. `0.3 A`C. `0.4 A`D. `0.5 A`

A tangent galvanometer has a reduction factor of 0. 2A . It gives a deflection of `45^(@)` when connected to a bettery of 6 V having internal resistance of `15 Omega` . Find the galvanometer resistance.

A bar magnet has magnetic moment 3.6 Am2 and pole strength 10.8 Am. Determine its magnetic length and geometric length.

Two tangent galvanometers P and Q connected in series . The number of turns in P is four times than of Q. When a current is passed through them P shows a deflection of `60^(@)` and Q shows a deflection of `30^(@)`. What is ratio of the radii of the coils of the two tangent galvanometers ?

A current of 10 A produces a deflection of `45^(@)` in a tangent galvanometer. What is the value of the current which will produce a deflection of `30^(@)` in the same galvanometer?

The period of oscillations of a magnet is 2 sec. When it is remagnetised so that the pole strength is 4 times its period will beA. 4 secB. 2 secC. 1 secD. `1//2 sec`

At a certain place a magnet makes 30 oscillations per minute. At another place where the magnetic field is double, its time period will beA. 4 secB. 2 secC. `(1)/(2)sec`D. `sqrt(2) sec`