Physics Part-I
Class 12
NCERT
1
Chapter 1: Electric Charges and Fields
47 questions
2
Chapter 2: Electrostatic Potential and Capacitance
46 questions
3
Chapter 3: Current Electricity
33 questions
4
Chapter 4: Moving Charges and Magnetism
41 questions
5
Chapter 5: Magnetism and Matter
36 questions
6
Chapter 6: Electromagnetic Induction
28 questions
7
Chapter 7: Alternating Current
37 questions
Q1
A sinusoidal voltage of peak value and frequency is applied to a series LCR circuit in which , and
(a) What is the frequency of the source at which resonance occurs? (b) Calculate the impedance, the current, and the power dissipated at the resonant condition.
(a) What is the frequency of the source at which resonance occurs? (b) Calculate the impedance, the current, and the power dissipated at the resonant condition.
Q2
At an airport, a person is made to walk through the doorway of a metal detector, for security reasons. If she/he is carrying anything made of metal, the metal detector emits a sound. On what principle does this detector work?
Q3
Show that in the free oscillations of an circuit, the sum of energies stored in the capacitor and the inductor is constant in time.
View all question8
Chapter 8: Electromagnetic Waves
20 questions
Question
Easy
Solving time: 2 mins
At an airport, a person is made to walk through the doorway of a metal detector, for security reasons. If she/he is carrying anything made of metal, the metal detector emits a sound. On what principle does this detector work?
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Text solution
Verified
The metal detector works on the principle of resonance in ac circuits. When you walk through a metal detector, you are, in fact, walking through a coil of many turns. The coil is connected to a capacitor tuned so that the circuit is in resonance. When you walk through with metal in your pocket, the impedance of the circuit changes - resulting in significant change in current in the circuit. This change in current is detected and the electronic circuitry causes a sound to be emitted as an alarm.
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Practice more questions from Physics Part-I (NCERT)
Q1
A sinusoidal voltage of peak value and frequency is applied to a series LCR circuit in which , and
(a) What is the frequency of the source at which resonance occurs? (b) Calculate the impedance, the current, and the power dissipated at the resonant condition.
(a) What is the frequency of the source at which resonance occurs? (b) Calculate the impedance, the current, and the power dissipated at the resonant condition.
Q2
At an airport, a person is made to walk through the doorway of a metal detector, for security reasons. If she/he is carrying anything made of metal, the metal detector emits a sound. On what principle does this detector work?
Q3
Show that in the free oscillations of an circuit, the sum of energies stored in the capacitor and the inductor is constant in time.
View allPractice questions from Physics Part-I (NCERT)
Question 1
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Question 2
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Question 3
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(b) Obtain the rms values of potential drops across each element.
(c) What is the average power transferred to
(d) What is the average power transferred to
the capacitor?
(e) What is the total average power absorbed by the circuit? [Average implies average value over one cycle.]
Question 4
Medium
Views: 5,699
The figure shows a series LCR circuit connected to a variable frequency source. , , .
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| Question Text | At an airport, a person is made to walk through the doorway of a metal detector, for security reasons. If she/he is carrying anything made of metal, the metal detector emits a sound. On what principle does this detector work? |
| Updated On | Feb 6, 2023 |
| Topic | Alternating Current |
| Subject | Physics |
| Class | Class 12 |
| Answer Type | Text solution:1 Video solution: 1 |
| Upvotes | 207 |
| Avg. Video Duration | 3 min |
