Competitive Exams: Physics MCQs (PracticeTest 27 of 35)

A material may be identified as being paramagnetic if it

can be permanently magnetised

gets magnetised ire a direction opposite to that of the applied field

exhibits strong magnetisation but only at very low temperatures

exhibits strong magnetisation when placed in a magnetic field at room temperature but not at very low temperatures


Three charges are arranged at the vertices of an equilateral triangle as shown in the given figure. The electric potential energy at the centre of the triangle will be approximately (assume q = 10 − 7 c and a = 0.1 m)

0.1J

0.01J

+ 0.01J

+ 0.1J


What should be the charge on a soap bubble of radius 1.0 cm in order that the pressure is the same inside and outside the bubble (Assume surface. Tension to be 32 dyne/cm)?

32 () p1/2 esu

32 p esu

(32) ½ p esu

(32) p2/1 esu


Charges Q and2Q are placed at some distance. The locus of points in the plane of the charges where the potential is zero will be

a straight line

a circle

a parabola

an ellipse


Assuming that the dipole moment of water is 5 × 10 cm, the value of the force of attraction between two water molecules will be of the order of

10 − 20 N

10 − 18 N

10 − 16 N

10 − 15 N


Two protons A and B are placed midway between the two plates of a parallel plate capacitor charged to a potential difference V as shown in the given figure. The forces on the two protons are:

not equal

equal but not zero

equal and zero

equal and V
