A balloon contains 1500 m$$^3$$ of He at 27$$\Upsilon$$C and 4 atmospheric pressure, the volume of He at $$-3\Upsilon$$C temperature and 2 atmospheric pressure will be
The sources of sound A and B produce a wave of 350 Hz in same phase. A particle P is vibrating under an influence of these two waves. If the amplitudes at P produced by the two waves is 0.3 mm and 0.4 mm, the resultant amplitude of the point P will be, when AP $$-$$ BP = 25 cm and the velocity of sound is 350 ms$$^{-1}$$
In a diffraction pattern due to a single slit of width $$a$$, the first minimum is observed at an angle $$30 \Upsilon$$ when light of wavelength $$500 \mathrm{~nm}$$ is incident on the slit. The first secondary maximum is observed at an angle of
Which statement(s) among the following are incorrect?
(i) A negative test charge experiences a force opposite to the direction of the field.
(ii) The tangent drawn to a line of force represents the direction of electric field.
(iii) The electric field lines never intersect.
(iv) The electric field lines form a closed loop.