magnetism

1.) The property of following magnetic lines of force through material is
A)	relative permeability
B)	permeability
C)	intensity of magnetisation
D)	susceptibility
2.) The magnetic length of a bar magnet is 10cm. Its geometric length is
A)	10 cm
B)	12 cm
C)	5 cm
D)	6 cm
3.) Screens to prevent the magnetic effects are made of
A)	Glass
B)	Wood
C)	Iron
D)	Brass
4.) A bar magnet of magnetic moment 5A-m2 has poles 20 cm apart its pole strength si
A)	50 A-m
B)	15 A-m
C)	25 A-m
D)	45 A-m
5.) In working with deflection magnetometer, the proportional error will be minimum when the deflection is
A)	o‘>30o
B)	o‘>45o
C)	o‘>60o
D)	o‘>90o
6.) A magnetised wire of moment 1.57 Am2 is bent in the form of a semicircle. The new magnetic moment will be
A)	2‘>0.1 Am2
B)	2‘>10 Am2
C)	2‘>1 Am2
D)	2‘>110 Am2
7.) Two small magnet produces no deflection when placed at 10cm and 20cm respectively on the two arms of a deflection magnetometer. The ratio of their magnetic moments is
A)	1:4
B)	1:8
C)	8:1
D)	4:1
8.) The ratio of magnetic inductions at distances r1 and r2 from a magnetic pole is___
A)	1 : r2‘>r1 : r2
B)	2 : r1‘>r2 : r1
C)	22 : r21‘>r22 : r21
D)	1 : 1
9.) The time period of a magnet at a place of magnetic field 4B is T. Time period at a place where magnetic field is B is
A)	2T
B)	3T
C)	4T
D)	16T
10.) Which of the following is best for permanent magnets is
A)	alnico
B)	iron
C)	steel
D)	Brass
11.) A magnetic field is produced and directed along y-axis. A magnet is placed along x-axis. The direction of torque on the magnet is
A)	in the x-y plane
B)	along y-axis
C)	along z-axis
D)	Torque will be zero
12.) The best method for demagnetisation is
A)	Dropping the magnet from some height
B)	Hammering the magnet
C)	Heating the magnet
D)	Sending alternating currents through the magnet
13.) Deflection magnetometer works on
A)	Coulomb’s law
B)	Curie law
C)	Tangent law
D)	The law of vibration of a magnet
14.) Find out the wrong statement
A)	The lines of force may intersect
B)	The lines of force never intersect
C)	The tangent drawn to the line of induction at any point gives the direction of magnetic induction at that point.
D)	None
15.) Vibration magnetometer works on the principle of
A)	Torque acting an the bar magnet
B)	Force acting on the bar magnet
C)	Both the force and the torque acting on the bar magnet
D)	None of the above
16.) The ratio of intensities of magnetic fields due to a short magnet in tan A and tan B position at the same distance is
A)	1:2
B)	2:1
C)	2:3
D)	1:4
17.) The acceleration aquired by the pole in the above problem is___
A)	2‘>2 m/s2
B)	2‘>20 m/s2
C)	2‘>4 m/s2
D)	2‘>40 m/s2
18.) Two magnets have their length in the ratio 2:3 and their pole strengths in the ratio 3:4. the ratio of their magnetic moment is
A)	2:1
B)	4:1
C)	1:2
D)	1:4
19.) The distance at which resultant induction becomes zero on the line joining the poles in the above problem is
A)	doesn’t form
B)	5cm
C)	10cm
D)	15cm
20.) In the above problem, The distance of each pole from the nearest end is
A)	2 cm
B)	4 cm
C)	1 cm
D)	5 cm
21.) Magnetic induction at a point in air at a distance 6cm away from a pole of strength 9 A-m is
A)	-3 T’>2.5 x 10-3 T
B)	-2 T’>2.5 x 10-2 T
C)	-5 T’>2.5 x 10-5 T
D)	-4 T’>2.5 x 10-4 T
22.) Two points A and B are located at equal distances from the centre of the short magnet on the axial line and equitorial line. The ratio of inductions at A and B is
A)	1:1
B)	2:1
C)	1:2
D)	4:1
23.) Two magnetic poles of strength 2 A-m each are separated by 10cm in air. The force between them is
A)	-5 N’>0.4 x 10-5 N
B)	-5 N’>0.04 x 10-5 N
C)	-5 N’>4 x 10-5 N
D)	-5 N’>40 x 10-5 N
24.) The time periods of a magnet in two fields are 1s and 4s, compare the two fields.
A)	4:1
B)	16:1
C)	1:16
D)	1:4
25.) The moments of inertia as well as the time periods of two magnets are in the ratio of 1:2. The ratio of their magnetic moments is
A)	2:1
B)	1:2
C)	4:3
D)	3:4

sound

1.) Longitudinal waves cannot be travel through
A)	solids
B)	liquids
C)	gases
D)	vaccum
2.) The echo and original sound differ in
A)	Frequency
B)	Velocity
C)	Intensity
D)	wavelength
3.) The type of the waves which cannot be transmitted through fluids
A)	longitudinal waves
B)	transverse waves
C)	electromagnetic waves
D)	Progressive waves
4.) Sound travels in rocks in the form of
A)	non-elastic waves
B)	only transverse elastic waves
C)	only longitudinal elastic waves
D)	both longitudinal and transverse elastic waves
5.) The waves which require material medium for their transmission are:
A)	Body waves
B)	Mechanical waves
C)	Sound waves
D)	All the above
6.) The phase differrence between two particles equidistant and lining on either side of a node is
A)	o‘>0o
B)	o‘>45o
C)	o‘>90o
D)	o‘>180o
7.) The property of a progressive wave that does not depend up on other characteristics
A)	Amplitude
B)	Frequency
C)	Wave velocity
D)	wavelength
8.) Hydrophone is based on
A)	Beats
B)	Echo
C)	Droppler effect
D)	Super position of sound waves
9.) Doppler effect is applicable to
A)	Sound waves
B)	Light waves
C)	Radio waves
D)	All the above
10.) An open window acts as
A)	Perfect reflector
B)	perfect absorber
C)	Both 1&2
D)	neither 1 nor 2
11.) Multiple reflections are observed in
A)	Stethoscope
B)	Reverberations
C)	Diffraction
D)	Both 1&2
12.) What determines the frequency of natural oscillations of system
A)	inertia
B)	elasticity
C)	mode of vibrations
D)	All the above.
13.) Resonance is a special case of
A)	free vibrations
B)	forced vibrations.
C)	Damped vibrations
D)	Maintained vibrations
14.) The longitudinal wave velocity in solids in bulk
A)	does not depend on wavelength and frequency
B)	depends on bulk modulus ‘k’ and rigidity modulus ‘n’.
C)	both
D)	none
15.) Sound waves can diffract easily because
A)	The wave length is very very small
B)	The wave length is more
C)	It can reflect
D)	It can refract
16.) The echo and original sound have same
A)	Frequency
B)	Amplitude
C)	Intensity
D)	All the above
17.) The longitudinal waves in air differ from the electromagnetic waves in that they cannot be
A)	Reflected
B)	Refracted
C)	diffracted
D)	polarised
18.) The persistance of sound in a hall is called
A)	resonance
B)	acoustics
C)	reverberations
D)	articulation
19.) Incase of damped oscillation amplitude
A)	decreases linearly
B)	increases linearly
C)	decreases exponentially
D)	increases exponentially
20.) If a string is vibrating in nth harmonic the total number of nodes produced is
A)	n-1
B)	n+1
C)	n+2
D)	n-2
21.) The waves which do not require any material medium for the propagation are:
A)	Matter waves
B)	Debroglie waves
C)	Electromagnetic waves
D)	Surface waves
22.) If a stretched string is plucked at the centre
A)	even harmonics are present
B)	odd harmonics are absent
C)	even harmonics are absent
D)	All harmonics are present
23.) When a tuning fork is heated its frequency
A)	increases
B)	decreases
C)	remains same
D)	become erratic
24.) At resonance
A)	The amplitude is maximum,theoretically infinite
B)	The amplitude is minimum
C)	Amplitude is zero
D)	Amplitude is either zero or minimum
25.) If a string be rubbed along its length,the vibrations are
A)	transverse
B)	longitudinal
C)	both 1 and 2
D)	neither 1 nor 2