Electricity and Magnetic Fundamentals

131. States that the ratio of the thermal conductivity is proportional to the absolute temperature for all metals.

1. Wien's displacement law
2. Hartleys law
3. Hall's law
4. Wiedemann Franz law

View answer

132. Steel is hard to magnetize because of its

1. Low permeability
2. High permeability
3. High density
4. High retentivity

View answer

133. Temporary magnets are commonly employed in

1. electric instruments
2. motors
3. moving coils loudspeakers
4. magnetos

View answer

134. The ability of a material to conduct magnetic flux through it.

1. Permittivity
2. Reluctivity
3. Conductivity
4. Permeability

View answer

135. The ability of a mechanically stressed ferromagnetic wire to recognize rapid switching of magnetization when subjected to a dc magnetic field.

1. Wartheim effect
2. Wiedemann effect
3. Wiegand effect
4. Edison effect

View answer

136. The air space between poles of magnets

1. Air gap
2. Free space
3. Vacuum
4. Atmosphere

View answer

137. The amount of magnetizing force to counter balance the residual magnetism of a magnetic material is referred to as

1. Reluctivity
2. Susceptivity
3. Coercivity
4. Retentivity

View answer

138. The B-H curve for _________ is a straight line passing through the origin.

1. cobalt
2. air
3. hardened steel
4. soft iron

View answer

139. The B-H curve of _________ is not a straight line.

1. air
2. wood
3. silicon steel
4. soft iron

View answer

140. The branch of Engineering which deals with the magnetic effect of electric current is known as

1. Magnetism
2. Electromagnetism
3. Electrical engineering
4. Electronics engineering

View answer