MEASUREMENT INSTRUMENTS Important Questions

 MEASUREMENT INSTRUMENTS Important Questions 


Q1. a dc Ammeter has resistance of 0.1 ohm and current range is (0-100)A . if the range is to be extended to (0 - 500)A , then meter requires shunt resistance of 
  • 0.010 ohm
  • 0.011 ohm 
  • 0.025 ohm 
  • 1.0 ohm
πŸ‘‰explanation 
m = 500/100 = 5 A
Rsh = (Rm) / (m - 1) = 0.1 / 4 = 0.025 ohm

Q2. an ammeter is obtained by shunting a 30 ohm galvanometer with 30 ohm resistance . what additional shunt should be connected across it to double the range ?
  • 15 ohm
  • 10 ohm
  • 5 ohm
  • 30 ohm
πŸ‘‰explanation 
Ammeter original  30 || 30 = 15 ohm
range double : m = 2 
Rsh = Rm / (m - 1) = 15 / 2-1 = 15 ohm

Q3. An ammeter of resistance Rm is placed as in an arrangement as shown in the figure material 
of Rm , Rsh is copper where as that of Rs , Rx is manganim . the condition for which the meter performance is compensated against temperature is 
  • 1 / Rm + 1 / Rsh = 1 / Rs + 1 / Rx
  • Rm Rs = Rsh Rx
  • Rm + Rx = Rsh + Rs
  • Rm / Rs = Rsh / Rx
Q4. The average value of the voltage wave v = 110 + 175 sin (314 t - 25) volt is 
  • 110 volt 
  • 175 volt 
  • 165.75 volt 
  • 206.7 volt 
Q5. The SI unit of conductivity is 
  • ohm - m
  • ohm / m
  • mho - m
  • mho / m
Q6. a resistance R is measured by ammeter voltmeter method the voltmeter reading is 200 v and its internely resistance is 2K . if  the ammeter reading is found to be 2A , then value of R 
  • 105.3 ohm 
  • 100.0  ohm 
  • 95.3 ohm 
  • 90.3 ohm
πŸ‘‰explanation 
R = 200 / 1.9 = 105.3

Q7. The multiplying power of the shunt of a multimeter is 8 , if the circuit current is 200 mA . then current through the meter is 
  • 25 mA
  • 1600 mA
  • 200 mA 
  • 3200 mA
πŸ‘‰explanation 
m = I / Im = total current / meter current 
               8 = 200 mA / Im 
               Im = 200 / 8 mA
                     =  25 mA
Q8. To increase the range of an ac ammeter you would use 
  • A consider across the meter 
  • current transformer
  • A potential transformer 
  • An induction across the meter 
Q9. the main advantage of the null balance technique of measurement is that
  • it does't load the medium
  • it give the center zero value at its input
  • it gives quick measurement 
  • it is not affected by temperature variation 
Q10. The range between the limits within which a quantity is measured received or transmitted expressed by stating the lower and upper limits is called the 
  • range 
  • span
  • range limit
  • none of above
Q11. The span of a zero centred voltmeter having a scale from  -10V to +10V is
  • 0 V
  • -10 V 
  • 10 V
  • 20 V
Q12. If two meters X and Y Required 40 Ma and 50 Ma respectively , to given full scale deflection then
  • X is more sensitive
  • Y is more sensitive 
  • Both X and Y are equally sensitive 
  • it would not be possible to assess the sensitivity on the basis of  given data 
πŸ‘‰explanation 
S = output / input 
X required to less input as compared to Y 

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