48 Science -- Current Electricity and Magnetism

The magnetic lines of force are closer why?

1 Answers

The magnetic lines of force are closer at the poles as the result the force is stronger at the poles but when they are away from the poles, the force is comparatively less strong.

A compass does not show the actual direction in the neutral points, why?

Germanium and silicon are also known as semiconductor, why? Give reason

On which factor does resistance depends on? Explain

From the formula of resistance, we have,

Resistance = Resisitivity * Length / Area

So, the resistance depends upon the following factors:

i) Resistivity of the material, which in turn is dependent upon the nature of the material and temperature

ii) Length of the material

iii) Cross sectional area of the material

The magnitude of angle of dip in the magnetic equator of the earth is zero, why?

The angle of dip in the magnetic south pole of the earth is 90 degree. Give reason

The angle of dip in the magnetic south pole of the earth is 90 degree because the needle remains vertically at the poles.

We should now the angle of declination to know the actual geographical direction of a certain place. Justify this statement.

Write any two difference between angle of dip and angle of inclination.

Ammeter is connected in series and voltmeter is connected parallel in an electric circuit, why?

Ammeter is the device used to measure the electric current. So, total current flowing through the circuit must pass through the ammeter. Therefore, it is connected in series. While voltmeter is the device used to measure the potential difference between two ends. Therefore, voltmeter is parallel to measure the potential difference across two ends.

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