1. In dc generator, wave winding is used for which type of machines ?

high voltage low current

high current low voltage

high voltage high current

low voltage low current

Answer: high voltage low current

Explanation:

In dc generator, wave winding is used for high voltage low current type of machines


2. The space to height ratio in illumination lies between ?

1 to 200

1 to 20

1 to 2

1 to 2000

Answer: 1 to 2

Explanation:

The space to height ratio in illumination lies between 1 to 2


3. Moulded case circuit breaker is used for ?

over load and short circuit protection

over load protection

short circuit protection

open circuit protection

Answer: over load and short circuit protection

Explanation:

Moulded case circuit breaker is used for over load and short circuit protection.


4. Which of the following will need lowest level of illumination ?

Displays

Fine engraving

Railway platform

Auditoriums

Answer: Railway platform

Explanation:

Railway platform will need lowest level of illumination.


5. A mercury vapour lamp gives ?

Pink light

Yellow light

Greenish blue light

White light

Answer: Greenish blue light

Explanation:

A mercury vapour lamp gives Greenish blue light.


6. Heat is transferred simultaneously by conduction, convection and radiation ............ ?

Inside boiler furnaces

During melting of ice

Through the surface of the insulated pipe carrying steam

From refrigerator coils to freezer of a refrigerator

Answer: Inside boiler furnaces

Explanation:

Heat is transferred simultaneously by conduction, convection and radiation Inside boiler furnaces.


7. Heavy-duty steel-works cranes having wide load variations are equipped with ?

DC series motors

Plain squirrel cage induction motors

Wound-rotor induction motors

Synchronous motors

Answer: DC series motors

Explanation:

Heavy-duty steel-works cranes having wide load variations are equipped with DC series motors


8. In induction heating ?

Heat is produced due to currents induced in the charge by electro-magnetic action.

The resistance of the charge must be low and voltage applied must be high in order to produce sufficient heat

Magnetic materials can be easily treated in comparison to non-magnetic materials

all option are correct

Answer: all option are correct

Explanation:

In induction heating Heat is produced due to currents induced in the charge by electro-magnetic action, The resistance of the charge must be low and voltage applied must be high in order to produce sufficient heat and Magnetic materials can be easily treated in comparison to non-magnetic materials.


9. The depth of penetration , in the case hardening of a steel pulley, required is 105mm. The relative permeability is unity and the specific resistance for steel is 5x10^-7 0hm-m. Determine the frequency required. ?

56.3 KHz

46.7 KHz

52.7 Khz

58.6 KHz

Answer: 56.3 KHz

Explanation:

The depth of penetration , in the case hardening of a steel pulley, required is 105mm. The relative permeability is unity and the specific resistance for steel is 5x10^-7 0hm-m. 56.3 KHz the frequency required.


10. When an electron breaks a covalent bond, and moves away ?

the semiconductor becomes conductor

a valency is created in broken covalent bond

the conductivity of the material increases

More ions are produced

Answer: a valency is created in broken covalent bond

Explanation:

When an electron breaks a covalent bond, and moves away a valency is created in broken covalent bond.