Find the ODD one out from the given

The unit of electric power is —  

A capacitor of 4 µF is charged to 100 V. It is then connected across an uncharged 2 µF capacitor. Final common voltage is:

A dielectric placed between the plates of a capacitor increases its:

Which of the following materials exhibits piezoelectric effect?

Ultrasonic waves, propagating through a medium, can be detected by:

The Pointing vector of electromagnetic waves has the same dimensions as that of:

If the specific heat at constant pressure Cₚ is greater than Cᵥ , the difference Cₚ -Cᵥ is equal to:

When is the magnetic field strength considered strongest?

What is the main difference between alternating current (AC) and direct current (DC)?  

Which one of the following determines the sharpness of image in a camera?