If the strength of the current flowing through a wire is increased, the strength of the magnetic field produced by it:

1. decreases
2. increases
3. remains the same
4. first increases then decreases

When a body vibrates under a periodic force, the vibrations of the body are always:

1. natural vibrations
2. damped vibrations
3. forced vibrations
4. resonant vibrations

Two notes are produced from two different musical instruments, such that they have same loudness and same pitch. The produced notes differ in their:

1. Waveform
2. Frequency
3. Wavelength
4. Speed

Choose the correct relation for e.m.f. (ε) and terminal voltage V:

1. ε = V [always]
2. V > ε [always]
3. V < ε [when the cell is in use]
4. None of these