Answer / raj

It depends on pulse repetition frequency

Answer / navneet

depends on prf.... its right

Answer / sanjay

depends mainly upon radiated power.

Answer / black_mamba_007

range of radar increased depends on



Transmitted power increase

received power decrease

frequency (decrease)but limited by wavwlength

diameter of the aperture




Actually it is affected by almost all the factors present in the radar range equation.

Answer / mhk

It is the max. length that one can measure using a RADAR without any ambiguity at a fixed PRF.

It is mainly depends on the pulse repetition frequency (PRF)

but also depends on the following factors:

transmitted power
min. detectable strength of the received signal
tx. antenna gain
Rx. antenna gain
directivity of antenna

Answer / rashi

400-500 hz

Answer / rohit kumar

>500hz

Answer / zahid

UPTO 500 HZ

Answer / niravpbhatt

Band Name Frequency Range Wavelength Range Notes
HF 3–30 MHz 10–100 m coastal radar systems, over-the-
horizon radar (OTH) radars; 'high frequency'
P < 300 MHz 1 m+ 'P' for 'previous', applied
retrospectively to early radar systems
VHF 50–330 MHz 0.9–6 m very long range, ground
penetrating; 'very high frequency'
UHF 300–1000 MHz 0.3–1 m very long range (e.g. ballistic
missile early warning), ground penetrating, foliage
penetrating; 'ultra high frequency'
L 1–2 GHz 15–30 cm long range air traffic control and
surveillance; 'L' for 'long'
S 2–4 GHz 7.5–15 cm terminal air traffic control, long-
range weather, marine radar; 'S' for 'short'
C 4–8 GHz 3.75–7.5 cm Satellite transponders; a compromise
(hence 'C') between X and S bands; weather
X 8–12 GHz 2.5–3.75 cm missile guidance, marine radar,
weather, medium-resolution mapping and ground surveillance;
in the USA the narrow range 10.525 GHz ±25 MHz is used for
airport radar. Named X band because the frequency was a
secret during WW2.
Ku 12–18 GHz 1.67–2.5 cm high-resolution mapping, satellite
altimetry; frequency just under K band (hence 'u')
K 18–24 GHz 1.11–1.67 cm from German kurz, meaning 'short';
limited use due to absorption by water vapour, so Ku and Ka
were used instead for surveillance. K-band is used for
detecting clouds by meteorologists, and by police for
detecting speeding motorists. K-band radar guns operate at
24.150 ± 0.100 GHz.
Ka 24–40 GHz 0.75–1.11 cm mapping, short range, airport
surveillance; frequency just above K band (hence 'a') Photo
radar, used to trigger cameras which take pictures of
license plates of cars running red lights, operates at
34.300 ± 0.100 GHz.
mm 40–300 GHz 7.5 mm – 1 mm millimetre band, subdivided as
below. The frequency ranges depend on waveguide size.
Multiple letters are assigned to these bands by different
groups. These are from Baytron, a now defunct company that
made test equipment.
Q 40–60 GHz 7.5 mm – 5 mm Used for Military communication.
V 50–75 GHz 6.0–4 mm Very strongly absorbed by the
atmosphere.
E 60–90 GHz 6.0–3.33 mm
W 75–110 GHz 2.7 – 4.0 mm used as a visual sensor for
experimental autonomous vehicles, high-resolution
meteorological observation, and imaging.
UWB 1.6–10.5 GHz 18.75 cm – 2.8 cm used for through the
wall radar and imaging systems.

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(1) Instrument is a device for determining (a) the magnitude of a quantity (b) the physics of a variable (c) either of the above (d) both (a) and (b) (2) Electronic instruments are preferred because they have (a) no indicating part (b) low resistance in parallel circuit (c) very fast response (d) high resistance in series circuit (e) no passive elements. (3) A DC wattmeter essentially consist of (a) two ammeters (b) two voltmeters (c) a voltmeter and an ammeter (d) a current and potential transformer (4) Decibel is a unit of (a) power (b) impedance (c) frequency (d) power ratio (5) A dc voltmeter may be used directly to measure (a) frequency (b) polarity (c) power factor (d)power (6) An accurate voltmeter must have an internal impedance of (a) very low value (b) low value (c) medium value (d) very high value (7) The insulation resistance of a transformer winding can be easily measured with (a) Wheatstone bridge (b) megger (c) Kelvin bridge (d) voltmeter (8) A 100 V voltmeter has full-scale accuracy of 5%. At its reading of 50 V it will give an error of (a) 10% (b) 5% (c) 2.5% (d) 1.25% (9) You are required to check the p. f. of an electric load. No p.f. meter is available. You would use: (a) a wattmeter (b) a ammeter, a voltmeter and a wattmeter (c) a voltmeter and a ammeter (d) a kWh meter (10) The resistance of a field coil may be correctly measured by using (a) a voltmeter and an ammeter (b) Schering bridge (c) a Kelvin double bridge (d) a Maxwell bridge (11) An analog instrument has output (a) Pulsating in nature (b) Sinusoidal in nature (c) Which is continuous function of time and bears a constant relation to its input (d) Independent of the input quantity (12) Basic charge measuring instrument is (a) Duddel's oscillograph (b) Cathode ray oscillograph (c) Vibration Galvanometer (d) Bailastic Galvanometer (e) Battery Charging equipment (13) A.C. voltage can be measured (using a d.c. instrument) as a value obtained (a) by subtracting the d.c. reading from it's a.c. reading. (b) Using the output function of the multimeter (c) By using a suitable inductor in series with it (d) By using a parallel capacitor with it (e) None of the above (14) A moving coil permanent magnet ammeter can be used to measure (a) D. C. current only (b) A. C. current only (c) A. C. and D. C. currents (d) voltage by incorporating a shunt resistance (e) none of these (15) Select the wrong statement (a) the internal resistance of the voltmeter must be high (b) the internal resistance of ammeter must be low (c) the poor overload capacity is the main disadvantage of hot wires instrument (d) the check continuity with multimeter, the highest range should be used. (e) In moving iron voltmeter, frequency compensation is achieved by connecting a capacitor across its fixed coil. (16) Which of the following instrument is suitable for measuring both a.c. and d.c. quantities. (a) permanent magnet moving coil ammeter. (b) Induction type ammeter. (c) Quadrant electrometer. (d) Moving iron repulsion type ammeter. (e) Moving iron attraction type voltmeter. (17) Swamping resistance is used in moving coil instruments to reduce error due to (a) thermal EMF (b) temperature (c) power taken by the instrument (d) galvanometer sensitivity. (18) A power factor meter is based on the principle of (a) electrostatic instrument (b) Electrodynamometer instrument (c) Electro thermo type instrument (d) Rectifier type instrument. (19) A potentiometer recorder is used for (a) AC singles (b) DC signals (c) both (a) and (b) (d) time varying signals (e) none of these. (20) Transformers used in conjunction with measuring instruments for measuring purposes are called (a) Measuring transformers (b) transformer meters (c) power transformers (d) instrument transformers (e) pulse transformers. (21) Leakage flux in an electrical machine is measure by (a) Ballistic galvanometer (b) Flux meter (c) Either (a) or (b) (d) Vibration galvanometer (e) CRO (22) A C.R.O. is used to indicate (a) supply waveform (b) magnitude of the applied voltage (c) B.H. loop (d) all of these (e) Magnitude of the current flowing in it. (23) An oscillator is a (a) an amplifier having feedback network (b) a high gain amplifier (c) a wide band amplifier (d) a untuned amplifier (e) None of these (24) Distortion can be measured by (a) Wave meter (b) Digital filters (c) Wein bridge circuit (d) Bridge T filter circuit (25) Series connected Q- meter is preferable for measurement of components having (a) high impedance (b) low impedance (c) both (a) and (b) (d) high frequency (e) low capacitance (26) A potentiometer is (a) an active transducer (b) a passive transducer (c) a secondary transducer (d) a digital transducer (e) a current sensing transducer (27) The basic components of a digital voltmeter are: (a) A/D converter and a counter (b) A/D converted and a rectifier (c) D/A converter and a counter (d) Ramp generator and counter (e) Comparator (28) Which of the following electrical equipment cannot convert ac into dc (a) diode (b) converter (c) transformer (d) mercury arc rectifier (29) Voltage measurement are often taken by using either a voltmeter or (a) an ammeter (b) an ohmmeter (c) an oscillator (d) a watt-meter (30)The electric device which blocks DC but allows AC is called: (a) capacitance (b) inductor (c) an oscilloscope (d) a watt-meter (31 ) The range of an ammeter can be extended by using a (a) shunt in series (b) shunt in parallel (c) multiplier in series (d) multiplier in parallel (32)A device that changes one form of energy to another is called (a) rheostat (b) oscillator (c) transducer (d) varicap (33) Aquadag is used in CRO to collect (a) primary electron (b) secondary electron (c) both primary and secondary (d) none of above (34) A vertical amplifier for CRO can be designed for (a) only a high gain (b) only a broad bandwidth (c) a constant gain time bandwidth product (d)all of the above (35) One of the following is active transducer (a) Strain gauge (b) Selsyn (c) Photovoltic cell (d) Photo emissive cell (36) The dynamic characteristics of capacitive transducer are similar to those of (a) low pass filter (b) high pass filter (c) band pass filter (d) band stop filter (37) Thermocouples are (a) passive transducers (b) active transducers (c) both active and passive transducers (d) output transducers (38) The size of air cored transducers as compare to iron core counter part are (a) bigger (b) smaller (c) same (39) From the point of view of safety, the resistance of earthing electrode should be: (a) low (b) high (c) medium (d) the value of resistance of electrode does not effect the safety (40) In CRT the focusing anode is located (a) between pre accelerating and accelerating anodes (b) after accelerating anodes (c) before pre accelerating anodes (d) none of above (41) Which transducer converts heat energy into electrical energy (a) I. V. D. T. (b) thermocouple (c) photoconductor (d) none of the above (42) Which of photoelectric transducer is used for production of electric energy by converting solar energy (a) photo emission cell (b) photo diode (c) photo transistor (d) both (b) and (c) (43) Which of the following instruments consumes maximum power during measurement? (a) induction instruments (b) hot wire instruments (c) thermocouple instruments (d) electrodynamometer instruments (44) Which of the following meters has the best accurancy (a) moving iron meter (b) moving coil meter (c) rectifier type meter (d) thermocouple meter (45) The function of the safety resistor in ohm meter is to (a) limit the current in the coil (b) increase the voltage drop across the coil (c) increase the current in the coil (d) protect the battery (46) Which of the following instruments is free from hysteresis and eddy current losses? (a) M.l. instrument (b) electrostatic instrument (c) electrodynamometer type instrument (d)all of these (47) The dielectric loss of a capacitance can be measured by (a) Wien bridge (b) Owen bridge (c) Schering bridge (d) Maxwell bridge (48) Reed frequency meter is essentially a (a) recording system (b) deflection measuring system (c) vibration measuring system (d) oscillatory measuring system (49) In measurements made using a Q meter, high impedance elements should preferably be connected in (a) star (b) delta (c) series (d) parallel (50) A digital voltmeter measures (a) peak value (b) peak-to-peak value (c) rms value (d) average value

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