A potentiometer is an accurate and versatile device to make electrical measurements of emf because the method involves a condition of no current flow through the galvanometer, the device can be used to measure potential difference, internal resistance of a cell and compare emf's of two sources. Q.

If the observer is moving away from the source ((Figure)), the observed frequency can be found: λs=vTo−voTovTs=(v−vo)Tov(1fs)=(v−vo)(1fo)fo=fs(v−vov).

Explanation: Most communication waves cannot transmit data accurately over long distances due to the curvature of the earth. They can only do so in the line of sight. However, they are not reflected by the ionosphere like radio waves and can be relayed to a wide area using geostationary satellites.

1. The change in velocity of an object at equal time intervals is called uniform acceleration.

2. A freely falling object is an example of uniform acceleration.

The correct order of radiations is in descending order of frequencies.

 X-rays > Infrared > Microwaves > Radio waves

Strong electrolytes have a degree of dissociation close to one, while weak electrolytes have a degree of dissociation less than one. Solvent nature: Solvents with a high dielectric constant show more dissociation. Dilution: As the solution is diluted, the degree of dissociation increases.