Related Questions

In a synchronous motor it the back e.m.f. generated in the armature at noload is approximately equal to the applied voltage, then
A the motor is said to be fully loaded
B the torque generated is maximum
C the excitation is said to be zero per cent
D the excitation is said to be hundred per cent
An over excited synchronous motor on noload is known as
A synchronous condenser
B generator
C induction motor
D alternator
Power amplifiers generally use transformer coupling because transformer per-mits
A Cooling of the circuit
B Impedance matching
C Distortionless output
D Good frequency response
If the supply frequency to the transformer is increased, the iron loss will
A not change
B decrease
C increase
D any of the above
Iron loss of a transformer can be measured by
A low power factor wattmeter
B unity power factor wattmeter
C frequency meter
D any type of wattmeter
If the number of atoms per unit volume of a monoatomic gas changes, the dielectric constant still remains constant.
A True
B False
For water evaporating into usaturated air under adiabatic conditions and at constant pressure, the __________ remains constant throughout the period of vaporisation.
A Dry bulb temperature
B Wet bulb temperature
C Humidity
D Relative saturation
গরম বাতাসে পরিপূর্ণ M ভরের একটি বেলুন (থ্রডি সহ) পৃথিবীর দিকে খুব ত্বরণ a তে নেমে আসছে। ঝুড়ি থেকে কি পরিমান m ভর ফেলে দিলে বেলুনটি উপরের দিকে একই খুব ত্বরন a- তে উঠে যাবে ? সকল ক্ষেত্রে বেলুনটির আয়তন একই ছিল বলে ধরে নেওয়া হলো। (g = অভিকর্ষীয় ত্বরন)(A hot air balloon with a bucket is descending towards the earth with a constant acceleration a. The combined mass of the balloon and bucket is M. What mass m from the bucket should be released so that the balloon starts ascending up with the same acceleration a? Consider the volume of the balloon remains constant at all the time. (g=acceleration due to gravity))
A m=2ag+aM
B m=g+a2M
C m=2ag M
D m=M2a(g+a)
E m=ag+M
Which of the following is the main advantage of an auto-transformer over a two-winding transformer?
A Eddy losses are totally eliminated
B Copper losses are negligible
C Saving in winding material
D Hysteresis losses are reduced
The output transformer used in a power amplifier is a ___________ transformer
A 1:1 ratio
B Step-up
C Step-down
D None of the above

Next steps