Description : Which of the following precautions should be taken when troubleshooting various power circuits using a common solenoid-type mechanical voltage tester (wiggins)? A. Never use this tester on circuits greater ... voltage expected in the circuit in order to prevent damage from an off-scale reading.
Last Answer : Answer: A
Description : Solenoid is a specially designed ________ A. Actuator B. Machine C. Electromagnet D. none of above
Last Answer : C. Electromagnet
Description : A compression spring is made of music wire of 2 mm diameter having a shear strength and shear modulus of 800 Mpa and 80 Gpa respectively. The mean coil diameter is 20mm, free length is 40 mm, and the number ... by 8 times b. decreased by 2 times c. increased by 2 times d. decreased by 8 times
Last Answer : a. increased by 8 times
Description : What happens to the bandwidth of an antenna as it is shortened through the use of loading coils? A. It is increased B. It is decreased C. No change occurs D. It becomes flat
Last Answer : A. It is increased
Description : As shown in the illustration, all 'MS' contacts are opened and closed by means of ________. EL-0073 A. operating coils B. magnets C. manual operation of the master switches D. solenoid switches
Last Answer : Answer: C
Description : What does The strength of an electromagnet depends on?
Last Answer : It depends on electrical current,the number of winding,and corematerials
Description : What are four ways you can increase the strength of an electromagnet?
Last Answer : Need answer
Description : True or False The strength of the magnetic poles in an electromagnet decreases with an increase in the number of turns of wire and the current flowing through them.?
Last Answer : FALSE
Description : The purpose of resistor bank 'R1-R5' in the winch circuit shown in the illustration is to ______________. EL-0102 A. limit armature current in lower and 'series field' current in hoist to ... required speeds D. regulate the strength of the brake solenoid 'B1-B2' in both directions of operation
Description : By inserting a soft iron piece into solenoid, what does the strength of the magnetic field?
Last Answer : Increase
Description : Strength of magnetic field of solenoid can be increased by adding core made of A. copper B. ferrous C. silver D. aluminum
Last Answer : ferrous
Description : What happens when you reverse the direction of the current in an electromagnet?
Last Answer : When you reverse current direction in an electromagnet, the magnetic poles will also change.
Description : What happens to the voltage in the secondary when the frequency of the supply in the primary is decreased? A) It increases B) It decreases C) It remains the same D) Cannot say unless the actual percentage increase in the frequency is known
Last Answer : What happens to the voltage in the secondary when the frequency of the supply in the primary is decreased? A) It increases B) It decreases C) It remains the same D) Cannot say unless the actual percentage increase in the frequency is known
Description : In a solenoid valve system if the voltage on the coil is 118 VAC and a continuity test of the solenoid and coil measures 80 ohms yet the solenoid will not allow water flow the most likely cause of?
Last Answer : There could be more than one reasons. Applied voltage may not be118 volts. Solenoid valve may have been stuck mechanically.Solenoid coil could be faulty, partially short.
Description : A synchronous motor maintains synchronism with the rotating field because _____________. A. field strength varies directly with rotor slip B. DC current applied to the rotor coils causes the rotor ... the flux created by the excitation current D. the stator flux rotates in the opposite direction
Last Answer : Answer: B
Description : If a synchronous motor begins to vibrate severely and pull out of synchronism, the cause may be ____________. A. an overload B. an open in the field coils C. no exciter voltage D. all of the above
Last Answer : Answer: D
Description : When troubleshooting motor controllers, a shorted relay or contactor coil is often indicated by _______________. A. a resistance reading of 'infinity' on an ohmmeter B. charred insulation and/or a blown ... of the coil's leads to ground D. a higher-than-normal voltage reading across the winding
Description : Excessive humming of AC contactors may be caused by ______________. A. burnt arc shields B. shorted armature coils C. a broken shading coil D. high voltage
Description : If coil 'R1-R2' on the transmitter in figure 'A' shown in the illustration is turned 30 degrees clockwise, corresponding coil 'R1-R2' on the receiver should ____________. EL-0092 A. make coils 'S1 ... a higher voltage depending on the turns ratio D. align itself to the same position if free to move
Description : Shading coils are installed on AC full-voltage starters to _____________. A. eliminate contact chatter B. dissipate opening contact arcs C. delay current build up in the holding coil D. protect the motor windings from momentary starting current overload
Description : A low voltage source is being used for testing armature coils. A coil short circuit will be indicated by a _______. A. high voltage reading, while the other coil readings will have an ... the other coil readings are steady D. steady voltmeter reading, while the other coil readings are fluctuating
Description : 4 Helical coils can be used on A. Low voltage side of high kVA transformers B. High frequency transformers C. High voltage side of small capacity transformers D. High voltage side of high kVA rating transformers
Last Answer : A) low voltage side of high KVA transformer
Description : Transformer voltage is maximum when two coils are (1) Normal to each other (2) Aligned along the same axis (3) 600 away from each other (4) 2700 away from each other
Last Answer : 2
Description : Which of these terms refers to loss of muscle and strength and decreased quality of muscle tissue?
Last Answer : scaropenia
Description : Which one of the following can be blocked by atropine? (a) Decreased blood pressure caused by hexamethonium (b) Increased blood pressure caused by nicotine (c) Increased skeleton muscle ... by neostigmine (d) Tachycardia caused by exercise (e) Tachycardia caused by infusion of acetylcholine
Last Answer : Ans: E
Description : __________ of a material results, when its strength is increased & ductility is decreased by heating at a relatively lower temperature after cold working. (A) Solid solution hardening (B) Screw dislocation (C) Strain ageing (D) Twinning
Last Answer : (C) Strain ageing
Description : The following are true about an action potential in a nerve fibre: a. it occurs when its membrane potential is hyperpolarized b. it is associated with a transient increase in membrane ... permeability to potassium d. it has an amplitude which varies directly to the strength of stimulus
Last Answer : there is a decreased in membrane permeability to potassium
Description : The effect of noradrenaline on the heart include: a. tachycardiac b. increased duration of the cardiac action potential c. decreased potassium conductance of the membranes of pacemaker cells d. increased strength of cardiac contraction
Last Answer : increased strength of cardiac contraction
Description : Pick up the incorrect statement from the following. If water cement ratio is (A) Increased, strength of concrete increases (B) Decreased, strength of concrete increases (C) Increased, strength of concrete is not affected (D) None of these
Last Answer : Answer: Option C
Description : Segregation of concrete (a) Increases the strength of concrete (b) Decreased the strength of concrete. (c) Not effect to strength of concrete. (d) None of these.
Last Answer : (b) Decreased the strength of concrete.
Description : High copper amalgam lasts longer than low copper amalgam because of:** A. Increased compressive strength B. Increased corrosion resistance C. High creep D. Increased tensile strength E. Decreased setting expansion
Last Answer : A. Increased compressive strength
Description : What is Ampere Pak ? What is the relationship between the polar energy of the electromagnet ?
Last Answer : The number of coils of the coil in the unit length of the electromagnetic marrow and the product of the current in the ampere unit is called ampere turn . The polar energy of an electromagnet is proportional to the ampere pound.
Description : How to change the pole of an electromagnet ?
Last Answer : The pole of an electromagnet can be changed by reversing the direction of current.
Description : The magnetic induction and the intensity of magnetic field inside an iron core of an electromagnet are `1 Wbm^(-2)` and `150Am^(-1)` respectively. The
Last Answer : The magnetic induction and the intensity of magnetic field inside an iron core of an electromagnet are `1 Wbm^(-2)` and ... (5)/pi` D. `10^(5)/(5 pi)`
Description : What Infrared rays are electromagnet waves that are longer than radio waves but shorter than visible light rays true of false?
Description : Is one of the major benefits of an electromagnet is that it can be turned on and off?
Last Answer : Yes, the electricity can be turned on and off and so the magnetis on or off
Description : How is an electromagnet different from a permeant magnet?
Last Answer : Mainly in that the electromagnet is NOT permanent. In otherwords, it can be switched on and off.Another relevant difference isthat the electromagnet constantly requires power, at least while itis on.
Description : How is a magnetic force in an electromagnet created?
Last Answer : An electromagnet uses electricity to create the magnetic field.Moving charges create magnetic fields. Knowing that, if we have alot of copper wire (with a suitable insulator) wrapped around aniron core ... around anail and connecting a battery to the ends of the wire will make asimple electromagnet.
Description : In an electromagnet the magnetic forces increase as increases?
Last Answer : It increases as the current increases.
Description : How does an electromagnet work in a headphone?
Last Answer : What is the answer ?
Description : Which of the following would be most suitable for making an electromagnet? (a) Copper (b) Tungsten (c) Soft iron (d) Steel
Last Answer : Ans:(c)
Description : Electromagnet is constructed with which of the following? (1) Steel (2) Soft Iron (3) Aluminium (4) Nickel
Last Answer : (2) Soft Iron Explanation: An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off. It is made of soft iron since it has the property of losing its magnetism very quickly.
Description : The most common type of AC service generator found aboard ship is the stationary _____________. A. electromagnetic field, revolving armature type B. electromagnetic field, oscillatory armature type C. armature, oscillatory electromagnet field type D. armature, rotating electromagnetic field type
Description : A molded-case circuit breaker provides protection against short circuits by using a/an ________________. A. electromagnet B. shading coil C. arc quencher D. burn away strip
Description : A molded-case breaker provides protection against short circuits by using a/an ____________. A. shading coil B. arc quencher C. electromagnet D. holding coil
Description : A direct current passing through a wire coiled around a soft iron core is the description of a simple ____________. A. magnetic shield B. electromagnet C. piezoelectric device D. electromagnetic domain
Description : Where a thermal-acting breaker is required to be used in an area of unusually high, low, or constantly fluctuating temperatures, an ambient compensating element must be used. This element consists of ... arm B. conical spring on the contact arm C. second bimetal element D. second electromagnet
Description : Which one of the following metals cannot be used as an electromagnet?
Last Answer : Copper
Description : What are electromagnetic waves? A. Alternating currents in the core of an electromagnet B. A wave consisting of two electric fields at right angles to each other C. A wave consisting of an electric field ... to each other D. A wave consisting of two magnetic fields at right angles to each other
Last Answer : C. A wave consisting of an electric field and a magnetic field at right angles to each other