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

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

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

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