Two coils of self inductance L₁ and L₂ are connected in series combination having mutual inductance of the coils as M. The equivalent self inductance of the combination will be :

A metallic conductor of length 1 m rotates in a vertical plane parallel to east-west direction about one of its end with angular velocity 5 rad s^$$-$$1. If the horizontal component of earth's magnetic field is 0.2 $$\times$$ 10^$$-$$4 T, then emf induced between the two ends of the conductor is :

Which is the correct ascending order of wavelengths?

For a specific wavelength 670 nm of light coming from a galaxy moving with velocity v, the observed wavelength is 670.7 nm. The value of v is :