A.C. Supply ? Viva Voice Question With Answer
For: Science Class 11 | Physics
Q.1: What is meant by electric current?
Ans. The flow of electrons.
Q.2: What are A.C. and D.C. currents?
Ans. Alternating current (A.C.) changes its direction with a definite frequency. The direct current (D.C.) flows in one direction only.
Q.3: What is meant by frequency?
Ans. Number of vibrations per sec.
Q.4: What is the frequency of A.C. in Nepal?
Ans. 50 cycles/s.
Q.5: What types of waves are produced in the thread?
Ans. Transverse stationary waves.
Q.6: What kind of vibrations are produced in the thread?
Ans. Forced vibrations.
Q.7: If the tension (T or Mg) is increased by four times what will be the effect on the length of one loop?
Ans. The relating f = (1/2l) ?Mg/m shows that length of the loop (l) will increase by two times.
Q.8: What will happen if supply D.C. current?
Ans. The rod will not vibrate because the soft iron piece will be magnetized in one direction only.
Q.9: What is the frequency of D.C.?
Q.10: Why the rod is vibrating?
Ans. The magnetic field produced by soft iron strip reverses its direction 50 times in each second.
Q.11: What is the function of bulb?
Ans. It shows that current is flowing in the circuit.
Q.12: If the iron rod is replaced by copper rod, will the rod vibrate?
Ans. No, copper is not attracted by a magnet.
Q.13: What is the relation between frequency of iron strip and frequency of waves in string in Melde?s apparatus?
Ans. The frequency of iron strip is equal to the frequency of waves in string.
Q.14: What is solenoid?
Ans. A solenoid is a coil of wire wound uniformly on cylinder having a length that is large compared with its radius. A uniform magnetic field is produced inside the coil, parallel to its axis, when the steady direct current is passed through it.
Q.15: What do you mean by stationary or standing waves?
Ans. When two exactly similar waves (same amplitude, frequency and time period) traveling in opposite directions with equal velocity superpose on one another in a confined medium (say pipe), the resultant wave obtained is called stationary or standing wave.
Q.17: What type of waves are formed in the string?
Ans. Transverse stationary waves are formed in the string.