1. Which type of material can be sensed by inductive proximity sensor?
a) Wooden type
b) Metallic type
c) Plastic type
d) Glass type
Explanation: Metallic type of material can be sensed by inductive proximity sensor. Inductive proximity sensor works on the principle of electromagnetic induction, that is it creates a magnetic field which induces an emf(electromotive force) which used to determine the presence of objects.
2. Will an infrared proximity sensor detect a black object when it comes in suitable range?
a) Yes, It will detect the object
b) No, It will not detect the object
c) Yes but it will produce random output
d) The sensor will stop working
Explanation: No, It will not detect the object if a black object comes in the range of an infrared proximity sensor. Since infrared proximity sensors work on reflection of Infrared ray from the objects but when these rays hit a black object, the ray gets absorbed and does not bounce back. So the sensor is unable to detect the object.
3. Which is the emf(electromotive force) induced in a coil if it has 8 turns and rate of change of flux with respect to time is 0.5?
a) -10 V
b) -25 V
c) 5.5 V
d) -4 V
Explanation: Given:
Number of turns(N)=8
Change of flux with respect to time(dΦ/dt)=0.5
Emf(electromotive force)(e)=-N*(dΦ/dt)
e=>-8*0.5=-4 V
-4 V is the emf (electromotive force) induced in a coil if it has 8 turns and rate of change of flux with respect to time is 0.5.
4. Which metal will have a larger range of detection by inductive proximity sensor?
a) Iron
b) Aluminium
c) Copper
d) Lead
Explanation: Iron will have a larger range of detection by inductive proximity sensor. A ferrous metal enables a longer range of detection where as non-ferrous metals can reduce the sensing range by 60%. Iron is a ferrous metal whereas all others are non-ferrous which is why iron will have a longer range of detection.
5. Which is has the number of turns in a coil if the emf (electromotive force) induced in it is -2.5V and rate of change of flux with respect to time is 0.5?
a) -1.5 V
b) -2.5 V
c) 5.5 V
d) -3 V
Explanation: Given:
Emf(electromotive force) induced in it is -2.5V
Change of flux with respect to time(dΦ/dt)=0.5
Emf(electromotive force)(e)=-N*(dΦ/dt)
-2.5=-N*0.5
N=5
Therefore, the coil has total 5 turns.
6. Inductive sensors are also referred as “NMR” coils. What does NMR stand for?
a) Nuclei Magneto resonance
b) Nuclei Magnetic resonator
c) Nuclear Magnetic resonator
d) Nuclear Magnetic resonance
Explanation: NMR stands for Nuclear Magnetic resonance. The “NMR (Nuclear Magnetic resonance)” coils detect the magnetic component of the EM (Electro-magnetic )field linked with the nuclear spin precession in Nuclear Magnetic resonance.
7. Which metal will have a larger range of detection by inductive proximity sensor?
a) Zinc
b) Steel
c) Copper
d) Lead
Explanation: Steel will have a larger range of detection by inductive proximity sensor. A ferrous metal enables a longer range of detection where as non-ferrous metals can reduce the sensing range by 60%. Steel is a ferrous metal whereas all others are non-ferrous which is why Steel will have a longer range of detection.
8. Which is the emf (electromotive force) induced in a coil if it has 10 turns and rate of change of flux with respect to time is 1?
a) -10 V
b) -25 V
c) 5.5 V
d) -3 V
Explanation: Given:
Number of turns(N) = 10
Change of flux with respect to time(dΦ/dt)=1
Emf(electromotive force)(e)=-N*(dΦ/dt)
e=>-10*1=-10 V
-10 V is the emf (electromotive force) induced in a coil if it has 10 turns and rate of change of flux with respect to time is 1.
9. Which type of proximity sensor can be used as touch sensor?
a) Inductive proximity sensor
b) Capacitive proximity sensor
c) Ultrasonic proximity sensor
d) Photoelectric proximity sensor
Explanation: Capacitive proximity sensor can be used as touch sensor. Capacitive proximity sensors can detect all objects that have a dielectric constant other than air. When a human finger comes in contact to the sensor, it immediately responds to this touch.
10. Which type of proximity sensor can detect a magnetic substance even if a wall of non-ferrous substance is made?
a) Magnetic proximity sensor
b) Capacitive proximity sensor
c) Ultrasonic proximity sensor
d) Photoelectric proximity sensor
Explanation: Magnetic proximity sensor can detect a magnetic substance even if a wall of non-ferrous substance is made. It can detect the objects beyond the normal limit of inductive proximity sensor. Since magnetic field can penetrate any wall made of ferrous substance, so they can easily detect a magnetic substance placed beyond the wall.