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

👉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

👉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

👉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

👉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 

👉explanation 

S = output / input 

X required to less input as compared to Y