Tag: physics

Questions Related to physics

The sides at 960 mm of 4 g. By what distance (in cm) will be the column be displaced is the tube is held verticle

physics hooke's law

  1. 4 cm

  2. 6 cm

  3. 9 cm

  4. 3 cm

  5. None of these

Show answer
Correct Option: E

A DMM is arragned at the magnetic pole of earth in $\tan{A}$ position. If a bar magnet is placed at some distance from the needle, deflection is

properties of magnet magnetism physics neutral points magnetic poles and magnetic compass magnetic field

  1. ${0}^{o}$

  2. ${90}^{o}$

  3. ${45}^{o}$

  4. ${180}^{o}$

Show answer
Correct Option: A

The needle of a dip circle shows an apparent dip of $45^o$ at a place and $60^o$ when the circle is rotated through $90^o$. The true dip is

properties of magnet magnetism physics neutral points magnetic poles and magnetic compass magnetic field

  1. $cos^{-1} \left (\cfrac 1{\sqrt 3}\right)$

  2. $cos^{-1} \left (\cfrac {\sqrt 3}{2}\right)$

  3. $cos^{-1} \left (\cfrac {1}{2}\right)$

  4. $cos^{-1} \left (\cfrac { 1}{\sqrt2}\right)$

Show answer
Correct Option: A

If earth's magnetic field $B _H$, if the frequency of oscillation of a magnetic needle is n, then -

properties of magnet magnetism physics neutral points magnetic poles and magnetic compass magnetic field

  1. $ n \propto B _H$

  2. $ n^2 \propto B _H$

  3. $ n \propto B _H^2$

  4. $n^2 \propto \frac{1}{B _H}$

Show answer
Correct Option: B

An aeroplane, in which the distance between the tips of the wings is $50 m$, is flying horizontally with a speed of $360$ km/hour, over a place where the vertical component of earth's magnetic field is $2.0 \times 10^{-4} \ tesla$ . The potential difference between the tips of the wings would be

properties of magnet magnetism physics neutral points magnetic poles and magnetic compass magnetic field

  1. $0.1 V$

  2. $0.5 V$

  3. $0.2 V$

  4. $1.0 V$

Show answer
Correct Option: D

In an uniform field the magnetic needle completes 10 oscillations in 92seconds. When a small magnet is placed in the magnetic meridian 10cm due north of needle with north pole towards south completes 15 oscillations in 69seconds. The magnetic moment of magnet ($B _H =0.3 \ G$) is

properties of magnet magnetism physics neutral points magnetic poles and magnetic compass magnetic field

  1. $4.5 \ A m^2$

  2. $0.45 \ A m^2$

  3. $0.75 \ A m^2$

  4. $0.225 \ A m^2$

Show answer
Correct Option: A

A magnetic needle is kept in a nonuniform magnetic field. It

properties of magnet magnetism physics neutral points magnetic poles and magnetic compass magnetic field

  1. may experience a force but certainly not a torque

  2. may experience a torque but certainly not a force

  3. may experience both a torque as well as force

  4. will certainly experience neither a force not a torque

Show answer
Correct Option: C
Explanation:

If magnet is placed parallel to the magnetic field then two poles of magnetic will experience different forces because of non uniform magnetic field. The forces will be in opposite direction therefore, there will be a net force also because forces are not equal. 
Now , when magnetic is not parallel to the magnetic field it will experience torque its a dipole placed in a field. Hence, (C)

The needle of a dip circle when place at a geomagnetic pole stays along

properties of magnet magnetism physics neutral points magnetic poles and magnetic compass magnetic field

  1. south-north direction only

  2. east-west direction only

  3. vertical direction

  4. horizontal direction

Show answer
Correct Option: C
Explanation:

Dip is the angle between the Earth's magnetic field and horizontal plane at that point. The needle of a dip circle when place at a geomagnetic poles stays along vertical direction.

Which of the following helps detecting the presence of magnetic field at a point ?

properties of magnet magnetism physics neutral points magnetic poles and magnetic compass magnetic field

  1. a strong magnet

  2. a solenoid

  3. a compass needle

  4. a current carrying wire

Show answer
Correct Option: C
Explanation:

A compass consists of a magnetized needle which tends to align in presence of a magnetic field, thus causing a deflection in the needle.

What kind of magnet  is used in a magnetic compass ?

properties of magnet magnetism physics neutral points magnetic poles and magnetic compass magnetic field

  1. electromagnet

  2. permanent magnet

  3. temporary magnet

  4. none of the above

Show answer
Correct Option: B
Explanation:

Magnetic compass is used for navigation and its magnetic needle is made of permanent magnet which is always aligned according to the earth's magnetic field.