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A carbon resistance reads Red – Red – Black. What is its resistance?

Value for first colour red is 2 Value for second colour red is also 2 The multiplier for black is... View Article

Two bulbs one of 50watt and another of 25 watt are connected in series to the mains. Find the ratio of the currents through them.

P = VI = I2R P1/P2 = V1/V2 ‘I’ will be constant here. As the bulbs are in series the same... View Article

What wire wound resistors made of?

Resistors can be wire bound or carbon resistors. Wire bound resistors are generally made of _____. Answer: Nichrome or Magnin... View Article

Resistance of a conductor depends on

length, area of cross-section, nature of material, temperature of conductor

In metals the major factor affecting the value of resistivity when temperature changes is

n does not change much in metals when temperature increases, but the value of τdecreases causing resistivity to increase.

A closed loop of wire is being moved so that it remains in a uniform magnetic field. The current induced in the coil is

Because when the loop remains in the field the magnetic flux remains constant. Therefore i = 0.

The device or arrangement to detect and check plane polarized light is called

The analyzer is the device or arrangement or the second Polaroid to detect whether the light is polarized or not.

If the light is completely polarized by reflection, then angle between the reflected and refracted light is

There is one particular angle of incidence, called polarizing angle (θp) or Brewster’s angle at which polarization of the reflected... View Article

The intensity of light transmitted by the analyzer is maximum when

According to Malus’s law Iαcos2θ, when θ=0o or 180o, I=Iocos20o = Io i.e the intensity of the light transmitted by the... View Article

For semiconductors, the major factor affecting the value of resistivity when temperature changes is

n increases with temperature and this increase more than compensates any decrease in relaxation time. Hence, for semiconductors resistivity decreases... View Article

Which type of materials shows the given below graph given below.

Resistivity of semiconductors decreases with increase in temperature. So, this graph must be of a semiconductor material.

A steady current flows in a metallic conductor of the non-uniform cross-section. The quantity/quantities constant along the length of the conductor is/are (1) current, electric field and drift speed (2) drift speed only (3) current and drift speed (4) current only

Answer: (4) current only When a steady current flows in a metallic conductor of non-uniform cross-section, the current flowing through the conductor is constant. Current does... View Article

The type of materials whose resistivity is affected on adding the impurity is known as

The resistivity of semiconductors decreases on adding the impurity.

The change in diffraction pattern of a single slit, when the monochromatic source of light is replaced by a source of white light will be

When a source of white light is used instead of a monochromatic source, the diffracted image of the slit gets... View Article

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