IITJEE physics questions

Question 1
A glass of soft drink with ice cubes floating on it is taken to an elevator which is accelerating in downwards direction. Then portion of ice inside softdrink
(a) increases
(b) decreases
(c) remains same
(d) depends on the density of soft drink

Question 2
A shell of mass m is at rest initially. It explodes into three fragments having masses in the ratio 2:2:1. THe fragments having equal masses fly off along mutuall perpandicular directions with speed v. What will be the speed of the third fragment.
(a) v
(b)√v
(c) 2√2 v
(d) 3√2 v

Question 3
If a particle moving in a magnetic field , increases its velocity, then its radius of magnetic field energy will

(a) remain constant
(b) decrease
(c) increase
(d) either b or c


Question 4
A particle of charge q and mass m moves in a circular orbit of radius r with angular speed ω. The ratio of magnitude of its magnetic moment to that of its angular momentum depends on

(a) q and m
(b) ω , m and q
(c) ω and q
(d) ω and m


Question 5
Two coils are placed close to each other. The mutual induction of the pair of coils depends upon

(a) rates at which currents are changing in the coil
(b) relative position and orientation of two coils
(c) the material of the wires of the coil
(d) the currents in the two coils


Question 6
An eye specialist prescribed spectacles having an combination of convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm . The power of this combination in diopters is

(a) +1.5
(b) -1.5
(c) +6.67
(d) -6.67


Question 7
To observe the phenomenon of interference, we need tow sources emitting light of

(a) nearly same frequency
(b) the same frequency
(c) different wavelengths
(d) same frequency and having definite phase relationship


Answers
1. c
2. c
3. c

4. a
5. b Mutual inductance of pair of coils depends on relative position and orientation of the two coils. This is in addition to other factors not given in the alternatives.
6. b use P=P1+P2 where p is total power of combination of lenses
7. d

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