Why frequency is 50 hz only & why should we maintain the frequency constant?

Why frequency is 50 hz only & why should we maintain the frequency constant?
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1 Answer

Answer :

 We can have the frequency at any frequency we like, but then we must also make our own motors, transformers or any other
equipment we want to use.
 We maintain the frequency at 50 Hz or 60hz because the world maintains a standard at 50 /60hz and the equipments are made to
operate at these frequency.
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Related questions

Why should be the frequency 50 Hz 60Hz only why not others like 45, 95 56 or anything , why should we maintain the frequency constant if so why it is only 50 Hz 60Hz?

Description : Why should be the frequency 50 Hz 60Hz only why not others like 45, 95 56 or anything , why should we maintain the frequency constant if so why it is only 50 Hz 60Hz?

Last Answer : We can have the frequency at any frequency you like, but than you must also make your own motors,high voltage transformers or any other equipment you want to use.We maintain the frequency at 50hz ... maintains a standard at 50 /60hz and the equipments are are made to operate at these frequency.

The line trap unit employed in carrier current relaying: (A) offers high impedance to 50 Hz power frequency signal (B) offers high impedance to carrier frequency signal (C) offers low impedance to carrier frequency signal (D) Both (A) & (C)

Description : The line trap unit employed in carrier current relaying: (A) offers high impedance to 50 Hz power frequency signal (B) offers high impedance to carrier frequency signal (C) offers low impedance to carrier frequency signal (D) Both (A) & (C)

Last Answer : Ans: B The line trap unit employed in carrier current relaying offers high impedance to carrier frequency signal. Because carrier frequency range is 35 km – 500 kHz XL = 2Π f l Where f increases XL will also increases

A 3 phase 50 Hz induction motor has full load speed of 970 rpm. Calculate no of poles and slip frequency.

Description : A 3 phase 50 Hz induction motor has full load speed of 970 rpm. Calculate no of poles and slip frequency.

Last Answer : The number of poles in an induction motor can be calculated using the following formula: No. of poles = (120 * frequency) / speed In this case, the number of poles would be calculated as follows: No. of poles = ( ... ) - 50 Hz = 8.08 Hz So the motor has 6 poles and a slip frequency of 8.08 Hz.

Slip of the induction machine is 0.02 and the stator supply frequency is 50 Hz. What will be the frequency of the rotor induced emf? (A) 10 Hz. (B) 50 Hz. (C) 1 Hz. (D) 2500 Hz.

Description : Slip of the induction machine is 0.02 and the stator supply frequency is 50 Hz. What will be the frequency of the rotor induced emf? (A) 10 Hz. (B) 50 Hz. (C) 1 Hz. (D) 2500 Hz.

Last Answer : Ans: C Given : s = 0.02 ; f = 50 Hz Therefore, frequency of rotor induced emf = s f = 0.02 x 50 = 1.0 Hz

The frequency of the rotor current in a 3 phase 50 Hz, 4 pole induction motor at full load speed is about (A) 50 Hz. (B) 20 Hz. (C) 2 Hz. (D) Zero.

Description : The frequency of the rotor current in a 3 phase 50 Hz, 4 pole induction motor at full load speed is about (A) 50 Hz. (B) 20 Hz. (C) 2 Hz. (D) Zero.

Last Answer : (C) 2 Hz.

A vehicle suspension system consists of a spring and a damper. The stiffness of the spring is 3.6 kN/m and the damping constant of the damper is 400 Ns/m. If the mass is 50 kg, then the damping factor (d ) and damped natural frequency (f n ), respectively, are a) 0.471 and 1.19 Hz b) 0.471 and 7.48 Hz c) 0.666 and 1.35 Hz

Description : A vehicle suspension system consists of a spring and a damper. The stiffness of the spring is 3.6 kN/m and the damping constant of the damper is 400 Ns/m. If the mass is 50 kg, then the damping factor (d ) and damped natural ... , are a) 0.471 and 1.19 Hz b) 0.471 and 7.48 Hz c) 0.666 and 1.35 Hz

Last Answer : a) 0.471 and 1.19 Hz

A vehicle suspension system consists of a spring and a damper. The stiffness of the spring is 3.6 kN/m and the damping constant of the damper is 400 Ns/m. If the mass is 50 kg, then the damping factor (d ) and damped natural frequency (f n ), respectively, are a) 0.471 and 1.19 Hz b) 0.471 and 7.48 Hz c) 0.666 and 1.35 Hz d) 0.666 and 8.50 Hz

Description : A vehicle suspension system consists of a spring and a damper. The stiffness of the spring is 3.6 kN/m and the damping constant of the damper is 400 Ns/m. If the mass is 50 kg, then the damping factor (d ) and damped natural ... .19 Hz b) 0.471 and 7.48 Hz c) 0.666 and 1.35 Hz d) 0.666 and 8.50 Hz

Last Answer : a) 0.471 and 1.19 Hz

Why we are using only 50 Hz for single and three phase electrical instruments?

Description : Why we are using only 50 Hz for single and three phase electrical instruments?

Last Answer : Synchronization condition: There are five conditions that must be met before the synchronization process takes place. The alternator must have equal line voltage, frequency, phase sequence, phase angle and waveform to that ... in the US and North America and 50 Hz in most of the rest of the world.

If the synchronous speed of a 12 pole, polyphase, induction motor operating at 60 Hz were 600 RPM, how many poles will be required in a similar motor operating at the same frequency but having a synchronous speed of 900 RPM? A. 4 B. 6 C. 8 D. 18

Description : If the synchronous speed of a 12 pole, polyphase, induction motor operating at 60 Hz were 600 RPM, how many poles will be required in a similar motor operating at the same frequency but having a synchronous speed of 900 RPM? A. 4 B. 6 C. 8 D. 18

Last Answer : Answer: C

If the electricity represented by the wave form in 'B' were applied to the left side of the illustrated circuit, the output on the right side would be ____________. EL-0064 A. direct current with the top lead positive with repect to the lower lead B. direct current, half wave rectified with a ripple frequency of 60 hz C. direct current with the top lead negative with repect to the lower lead D. clipped to a value equal to the square root of 3 times the input voltage value

Description : If the electricity represented by the wave form in 'B' were applied to the left side of the illustrated circuit, the output on the right side would be ____________. EL-0064 A. direct current with the ... lower lead D. clipped to a value equal to the square root of 3 times the input voltage value

Last Answer : Answer: C

Assuming a standard 60 Hz. input to the circuit shown in the illustration, the ripple frequency would be ____________. EL-0085 A. 30 Hz B. 60 Hz C. 90 Hz D. 120 Hz

Description : Assuming a standard 60 Hz. input to the circuit shown in the illustration, the ripple frequency would be ____________. EL-0085 A. 30 Hz B. 60 Hz C. 90 Hz D. 120 Hz

Last Answer : Answer: D

If the clock frequency to the circuit shown in the illustration were 2 kHz, what would be indicated at the output of 'FF-C'? EL-0087 A. 250 Hz B. 666 Hz C. 6 kHz D. 16 kHz

Description : If the clock frequency to the circuit shown in the illustration were 2 kHz, what would be indicated at the output of 'FF-C'? EL-0087 A. 250 Hz B. 666 Hz C. 6 kHz D. 16 kHz

Last Answer : Answer: A

What will happen if Transformer is operated at 100 HZ Frequency?

Description : What will happen if Transformer is operated at 100 HZ Frequency?

Last Answer : 1. As per EMF equation of the transformer frequency is directly proportional to winding voltage. If we double the frequency the sinusoidal root mean winf=ding voltage also doubled. E=4.44 * f*b*n* ... core 5) This is followed by heating up of the oil and thus cooling temperature goes down sharply.

A carrier signal has ______. A. Constant peak amplitude B. The information C. Frequency range 20-20000 Hz D. A varying amplitude

Description : A carrier signal has ______. A. Constant peak amplitude B. The information C. Frequency range 20-20000 Hz D. A varying amplitude

Last Answer : A. Constant peak amplitude

The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density.

Description : The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is :  (A) 256 W (B) 320 W (C) 500 W (D) 625 W

Last Answer : The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is : 625 W

The frequency of direct current is __. (1) Zero (2) 50 HZ (3) 60 HZ (4) 100 HZ

Description : The frequency of direct current is __. (1) Zero (2) 50 HZ (3) 60 HZ (4) 100 HZ

Last Answer : (1) Zero Explanation: Direct Current (DC) refers to power systems that use only one polarity of voltage or current, and to refer to the constant, zero-frequency, or slowly varying local mean value of a voltage or current.

A cantilever shaft having 50 mm diameter and length of 300 mm has a disc of mass 100 kg at its free enD. The Young’s modulus for the shaft material is 200 GN/m 2 . Calculate the natural longitudinal frequency in Hz. A. 575B. 625 C. 525 D. 550

Description : A cantilever shaft having 50 mm diameter and length of 300 mm has a disc of mass 100 kg at its free enD. The Young’s modulus for the shaft material is 200 GN/m 2 . Calculate the natural longitudinal frequency in Hz. A. 575B. 625 C. 525 D. 550

Last Answer : A. 575

A weight of 50 N is suspended from a spring of stiffness 4000N/m and subjected to a harmonic force of magnitude 60N and frequency 60 Hz. what will be the static displacement of the spring due to maximum applied force A. 0.015m B. 0.15 m C. 15 m D. 150m

Description : A weight of 50 N is suspended from a spring of stiffness 4000N/m and subjected to a harmonic force of magnitude 60N and frequency 60 Hz. what will be the static displacement of the spring due to maximum applied force A. 0.015m B. 0.15 m C. 15 m D. 150m

Last Answer : B. 0.15 m

A cantilever shaft having 50 mm diameter and length of 300 mm has a disc of mass 100 kg at its free end. The Young’s modulus for the shaft material is 200 GN/m 2 . Calculate the natural longitudinal frequency in Hz. a) 575 b) 625 c) 525 d) 550

Description : A cantilever shaft having 50 mm diameter and length of 300 mm has a disc of mass 100 kg at its free end. The Young’s modulus for the shaft material is 200 GN/m 2 . Calculate the natural longitudinal frequency in Hz. a) 575 b) 625 c) 525 d) 550

Last Answer : a) 575

The frequency of direct current is _______ (1) Zero (2) 50 HZ (3) 60 HZ (4) 100 HZ

Description : The frequency of direct current is _______ (1) Zero (2) 50 HZ (3) 60 HZ (4) 100 HZ

Last Answer : Zero

The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open

Description : The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open circuited. The rotor is made to rotate at a speed of 600 rpm in the opposite direction to the ... frequency of induced voltage across slip ring is A) 30 Hz B) 70 Hz C) 20 Hz D) 35 Hz

Last Answer : The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open circuited. The rotor is made to rotate at a speed of 600 rpm in the opposite direction to the normal direction, The frequency of induced voltage across slip ring is 70 Hz

In a full wave rectifier with input frequency of 50 Hz, the frequency of the output is:

Description : In a full wave rectifier with input frequency of 50 Hz, the frequency of the output is: (1) 50 Hz (2) 100 Hz (3) 150 Hz (4) 200 Hz

Last Answer : In a full wave rectifier with input frequency of 50 Hz, the frequency of the output is: 100 Hz

The reactance offered by a capacitor to an alternating current of frequency 50 Hz is 10 ohm. If frequency is

Description : The reactance offered by a capacitor to an alternating current of frequency 50 Hz is 10 ohm. If frequency is increased to 100 Hz, the reactance will be (a) 2.5 ohm (b) 5.0 ohm (c) 20.0 ohm (d) 40.0 ohm 

Last Answer : Xc = 1/(2*pi*f*c) so when f is double .... Xc will be half ... Ans is 5ohm

The corona loss in a 50 Hz system is 0.25 kW/ph/km. At a frequency of 60 Hz, the corona loss

Description : The corona loss in a 50 Hz system is 0.25 kW/ph/km. At a frequency of 60 Hz, the corona loss would be   (a) 0.30 kW/ph/km (b) 0.36 kW/ph/km (c) 028 kW/ph/km (d) 0.21 kW/ph/km

Last Answer : The corona loss in a 50 Hz system is 0.25 kW/ph/km. At a frequency of 60 Hz, the corona loss would be 028 kW/ph/km

What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to

Description : What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage:  (A) Eddy Current and Hysteresis losses will be ... Current will be too much high  (C) Transformer may start to smoke and burn  (D) No effect

Last Answer : What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage:  (A) Eddy Current and Hysteresis losses will be ... will be too much high  (C) Transformer may start to smoke and burn  (D) No effect

For a 500 Hz frequency excitation, a 50 km long power line will be modeled as

Description : For a 500 Hz frequency excitation, a 50 km long power line will be modeled as

Last Answer : For a 500 Hz frequency excitation, a 50 km long power line will be modeled as long line

The input frequency is 50 Hz. The ripple frequency in a 12 phase full wave rectifier is

Description : The input frequency is 50 Hz. The ripple frequency in a 12 phase full wave rectifier is (A) 1200 Hz (B) 600 Hz (C) 100 Hz (D) 50 Hz 

Last Answer : The input frequency is 50 Hz. The ripple frequency in a 12 phase full wave rectifier is 1200 Hz

lf slip of an induction machine is 0.02 and the stator supply frequency is 50 Hz, what will be the frequency...

Description : lf slip of an induction machine is 0.02 and the stator supply frequency is 50 Hz, what will be the frequency of the rotor induced e.m.f.? (A) 10 Hz (B) 50 Hz (C) 1 Hz (D) 2500 Hz

Last Answer : 1hz

The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q....

Description : The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes_____ohms.

Last Answer : The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes 10 ohms.

A sine wave has a frequency of 50 Hz. Its angular frequency is _______ radian/second.

Last Answer :  A sine wave has a frequency of 50 Hz. Its angular frequency is 100 n radian/second.

if voltage is 230 Volts , frequency is 50 Hz and current is 1 ampere then what will be the resistance?

Description : if voltage is 230 Volts , frequency is 50 Hz and current is 1 ampere then what will be the resistance?

Last Answer : As V = 230v and I = 1A Therfore by ohm's law V =IR R = V/I =230/1 =230 ohm

Can 60 Hz transformers be operated at 50 Hz?

Description : Can 60 Hz transformers be operated at 50 Hz?

Last Answer : The transformers rated below 1 KVA can be used on 50 Hz service. Transformers 1 KVA and larger, rated at 60 Hz, should not be used on 50 Hz service, due to the higher losses and resultant heat ... designs are required for this service. However, any 50 Hz transformer will operate on a 60 Hz service.

Why 50 Hz chosen?

Description : Why 50 Hz chosen?  

Last Answer : Earlier 25 Hz generally used. After developing of the high-speed turbine, 50/60 Hz standardized. 

A 220/440 V, 50 Hz, 5 KVA, single phase transformer operates on 220V, 40Hz supply with secondary winding open circuited. Then (A) Both eddy current and hysteresis losses decreases. (B) Both eddy current and hysteresis losses increases. (C) Eddy current loss remains the same but hysteresis loss increases. (D) Eddy current loss increases but hysteresis loss remains the same.

Description : A 220/440 V, 50 Hz, 5 KVA, single phase transformer operates on 220V, 40Hz supply with secondary winding open circuited. Then (A) Both eddy current and hysteresis losses decreases. (B) Both ... same but hysteresis loss increases. (D) Eddy current loss increases but hysteresis loss remains the same.

Last Answer : (A) Both eddy current and hysteresis losses decreases.

A 3-phase, 400 votts, 50 Hz, 100 KW, 4 pole squirrel cage induction motor with a rated slip of 2% will have a rotor speed of (A) 1500 rpm (B) 1470 rpm (C) 1530 rpm (D) 1570 rpm

Description : A 3-phase, 400 votts, 50 Hz, 100 KW, 4 pole squirrel cage induction motor with a rated slip of 2% will have a rotor speed of (A) 1500 rpm (B) 1470 rpm (C) 1530 rpm (D) 1570 rpm

Last Answer : Ans: B N = NS (1-S) and NS =120 f / p =120 x 50 /4 = 1500 rpm ∴N= 1500 (1-0.02) =1470 rpm

The eddy current loss in an a-c electric motor is 100 watts at 50 Hz. Its loss at 100 Hz will be (A) 25 watts (B) 59 watts (C) 100 watts (D) 400 watts

Description : The eddy current loss in an a-c electric motor is 100 watts at 50 Hz. Its loss at 100 Hz will be (A) 25 watts (B) 59 watts (C) 100 watts (D) 400 watts

Last Answer : (D) 400 watts

A balanced three-phase, 50 Hz voltage is applied to a 3 phase, 4 pole, induction motor. When the motor is delivering rated output, the slip is found to be 0.05. The speed of the rotor m.m.f. relative to the rotor structure is (A) 1500 r.p.m. (B) 1425 r.p.m. (C) 25 r.p.m. (D) 75 r.p.m.

Description : A balanced three-phase, 50 Hz voltage is applied to a 3 phase, 4 pole, induction motor. When the motor is delivering rated output, the slip is found to be 0.05. The speed of the rotor m.m.f. relative to the rotor structure is (A) 1500 r.p.m. (B) 1425 r.p.m. (C) 25 r.p.m. (D) 75 r.p.m.

Last Answer : (D) 75 r.p.m.

The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply. The secondary output voltage will be (A) 3.6 V. (B) 2.5 V. (C) 3.0 V. (D) 6.0 V.

Description : The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply. The secondary output voltage will be (A) 3.6 V. (B) 2.5 V. (C) 3.0 V. (D) 6.0 V.

Last Answer : (C) 3.0 V.

A 100 MVA, 11 KV, 3-phase, 50 Hz, 8—pole synchronous generator has an inertia constant H equal to

Description : A 100 MVA, 11 KV, 3-phase, 50 Hz, 8—pole synchronous generator has an inertia constant H equal to 4 seconds. The stored energy in the rotor of the generator at synchronous speed will be  A) 100 MJ B) 400 MJ C) 800 MJ D) 12.5 MJ

Last Answer : 800

A 50 Hz, 4 pole turboalternator rated at 20 MVA. 13.2 KV has an inertia constant H = 4 KW sec/KVA.

Description : A 50 Hz, 4 pole turboalternator rated at 20 MVA. 13.2 KV has an inertia constant H = 4 KW sec/KVA. The K.E. stored in the rotor at synchronous speed is

Last Answer : A 50 Hz, 4 pole turboalternator rated at 20 MVA. 13.2 KV has an inertia constant H = 4 KW sec/KVA. The K.E. stored in the rotor at synchronous speed is 80 MJ

A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc

Description : A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is (A) 4.5 V (B) 6.75 V (C) 9 V (D) 13.5 V

Last Answer : A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is 9 V

Two AC generators of the same capacity are operating in parallel. One with a zero speed droop setting and the other with a 5% speed droop. If its capacity is not exceeded, the unit whose governor has the zero speed droop setting will _____________. A. assume the smaller share of the load B. maintain the frequency of the system C. have poor sensitivity characteristics D. have poor power response

Description : Two AC generators of the same capacity are operating in parallel. One with a zero speed droop setting and the other with a 5% speed droop. If its capacity is not exceeded, the unit whose ... B. maintain the frequency of the system C. have poor sensitivity characteristics D. have poor power response

Last Answer : Answer: B

Even though the main engine runs at varying speeds, how does the alternator maintain constant frequency?

Description : Even though the main engine runs at varying speeds, how does the alternator maintain constant frequency?

Last Answer : By use of thyristor controlled frequency (rpm) converters.

In the illustrated electronic governor, the circuit card connected to the potential and current transformers is for ________. EL-0046 A. increasing the signal strength to the governor to maintain constant engine speed with increased load B. send a kilowatt signal to the metering circuit C. shutting down the prime mover in the event of reverse power to protect from motorization D. conditioning the load through the use of a magnetic amplifier current transformer

Description : In the illustrated electronic governor, the circuit card connected to the potential and current transformers is for ________. EL-0046 A. increasing the signal strength to the governor to ... from motorization D. conditioning the load through the use of a magnetic amplifier current transformer

Last Answer : Answer: A

The purpose of an impressed current cathodic protection system aboard ship is to _______________. A. prevent corrosion of the hull, propeller, rudder and line shafting B. neutralize the vessel's stray magnetic fields which would interfere with radar C. protect engine room and deck machinery from oxidation in the presence of salt air D. maintain a minimum constant alternator load to prevent overheating

Description : The purpose of an impressed current cathodic protection system aboard ship is to _______________. A. prevent corrosion of the hull, propeller, rudder and line shafting B. neutralize the vessel's ... the presence of salt air D. maintain a minimum constant alternator load to prevent overheating

Last Answer : Answer: A

The purpose of the 'heater resistors' for the winch circuit shown in the illustration is to _______________. EL-0102 A. limit the current in the heater circuit B. dispel moisture in the 'master switch' housing & control panel C. keep the winch brake housing below the dew point D. maintain winch motor operating temperature

Description : The purpose of the 'heater resistors' for the winch circuit shown in the illustration is to _______________. EL-0102 A. limit the current in the heater circuit B. dispel moisture in the ' ... panel C. keep the winch brake housing below the dew point D. maintain winch motor operating temperature

Last Answer : Answer: B

Heating 235 g of water from 22.6 degrees C to 94.4 degrees C in a microwave oven requires 7.06x10^4 J of energy. If the microwave frequency is 2.88x10^10 Hz, how many quanta are required to supply the 7.06x10^4 J?

Description : Heating 235 g of water from 22.6 degrees C to 94.4 degrees C in a microwave oven requires 7.06x10^4 J of energy. If the microwave frequency is 2.88x10^10 Hz, how many quanta are required to supply the 7.06x10^4 J?

Last Answer : answer:Guidelines. I don’t mean to be the bearer of bad news…

The frequency of a source of sound is 200 hz.How many Times does it vibrate in 2 min? -Physics

Description : The frequency of a source of sound is 200 hz.How many Times does it vibrate in 2 min? -Physics

Last Answer : Hence, the source vibrates 12000 times in a minute, producing a frequency of 00 Hz.

which of the following animals could detect sound at a frequency of 67,000 hz? -General Knowledge

Description : which of the following animals could detect sound at a frequency of 67,000 hz? -General Knowledge

Last Answer : Dogs could detect sound at a frequency of 67,000 Hz.

The mean velocity of blood flow in the aorta during systole is 1.5 × 10–2 m / s. What is the frequency change in an instrument with a signal frequency of 105 Hz (speed of sound in blood, 1570 m / s)?

Description : The mean velocity of blood flow in the aorta during systole is 1.5 × 10–2 m / s. What is the frequency change in an instrument with a signal frequency of 105 Hz (speed of sound in blood, 1570 m / s)?

Last Answer : 1060 kg/m3, very close to pure water's density of 1000 kg/m3. The average adult has a blood volume of roughly 5 litres (11 US pt) or 1.3 gallons, which is composed of plasma ... .4 million (female) erythrocytes: Red blood cells contain the blood's hemoglobin and distribute oxygen. Mature red blood