Download Measurements and Uncertainties: Practice Problems and more Exams Public Health in PDF only on Docsity!
Measurements And Uncertainties Problems
Which is a unit of force? a. J m b. J m^- c. J m s^- d. J m^-1 s โ Ans - b. J m^- How many significant figures are there in the number of 0.0450? a. 2 b. 3 c. 4 d. 5 โ Ans - b. 3 What is the unit of electrical energy in fundamental SI units? a. kg m^2 C^-1 s b.kg m s^- c. kg m^2 s^- d. kg m^2 s^-1 A โ Ans - c. kg m^2 s^- Which of the following expresses the watt in terms of fundamental units? a. kg m^2 s b. kg m^2 s^- c. kg m^2 s^- d. kg m^2 s^-3 โ Ans - d. kg m^2 s^- Which of the following contains one fundamental and one derived unit? a. ampere and kilogram b. ampere and coulomb c. joule and newton d. joule and coulomb โ Ans - b. ampere and coulomb Which of the following is a fundamental unit? a. Ampere b. Coulomb c. Ohm d. Volt โ Ans - a. Ampere
The radius of a sphere is measured with an uncertainty of 2%. What is the uncertainty in the volume of the sphere? a. 2% b. 4% c. 6% d. 8% โ Ans - c. 6% Which of the following reduce random errors in an experiment? a. Using an instrument having a greater precision b. Checking the calibration fo the instruction used c. Checking for zero error on the instrument used d. Repeating readings โ Ans - d. Repeating readings The force of air resistance F that acts on a car moving at speed v is given by F = kv^2 where k is a constant. What is the unit of k? a. kg m^- b. kg m^-2 s^ c. kg m^- d. kg m^-2 s^-2 โ Ans - a. kg m^- The volume V of a cylinder of radius R and height H is given by V = ฯR^2H. The volume of the cylinder was measured with an uncertainty of 10% and the height was measured with an uncertainty of 6%. What is the uncertainty in the radius of the cylinder? a. 1% b. 2% c. 4% d. 8% โ Ans - d. 8% The vector diagram shows two fores acting on a point object O. The forces are in the plane of the page. Vector Diagram: 3 N force pulling O upward and 4 N force pulling O in the rightward direction. Another 5 N force is applied to O int he plane of the page. Which of the following gives the direction of this force to ensure that O is in equilibrium? a. up and right b. down and left c. down and right
Which one of the following lists a fundamental unit and a derived unit? a. ampere and second b. coulomb and kilogram c. coulomb and newton d. meter and kilogram โ Ans - b. coulomb and kilogram The resistive force F acting on a sphere of radius r moving at speed v through a liquid is given by F = cvr, where c is a constant. Which of the following is a correct unit for c? a. N b. N s^- c. N m^2 s^- d. N m^2 s โ Ans - d. N m^2 s Sub-multiples of units may be expressed using a prefix. Which one of the following lists the prefixes in decreasing order of magnitude? a. centi- micro- milli- nano- b. milli- centi- nano- micro- c. centi- milli- micro- nano- d. milli- micro- centi- nano- โ Ans - c. centi- milli- micro- nano- The resistive force F that acts on an object moving at speed v in a stationary fluid of constant density is given by the expression F = kv^2, where k is a constant. State the derived units of force F and speed v. Determine the derived units of k. โ Ans - kg m s^- m s^- kg m^- Which of the following contains only fundamental SI units? a. ampere, newton, second b. volt, second, kelvin c. mole, ampere, kilogram d. kilogram, meter, tesla โ Ans - c. mole, ampere, kilogram Which one of the following contains three fundamental units? a. Meter, Kilogram, Coulomb b. Second, Ampere, Newton c. Kilogram, Ampere, Kelvin d. Kelvin, Coulomb, Second โ Ans - c. Kilogram, Ampere, Kelvin
Which one of the following is a fundamental unit in the SI system? a. Ampere b. Volt c. Ohm d. Tesla โ Ans - a. Ampere Which one of the following is a fundamental unit? a. Coulomb b. Ohm c. Volt d. Ampere โ Ans - d. Ampere The mass of a body is measured to be 0.600 kg and its acceleration to be 3 m s^-2. The net force on the body, expressed to the correct number of significant figures is a. 1.8 N b. 1.80 N c. 2 N d. 2.0 N โ Ans - c. 2 N A student measures the current in a resistor as 677 mA for a potential difference of 3.6 V. A calculator shows the resistance of the resistor to be 5.31757775 Ohms. Which one of the following gives the resistance to an appropriate number of significant figures? a. 5.3 Ohms b. 5.32 Ohms c. 5.318 Ohms d. 5.31785775 Ohms โ Ans - a. 5.3 Ohms When a voltage of 12.2 V is applied to a DC motor, the current I in the motor is 0.20 A. Which one of the following is the output power VI of the motor given to the correct appropriate number of significant digits? a. 2 W b. 2.4 W c. 2.40 W d. 2.44 W โ Ans - b. 2.4 W
b. 1 : 10 c. 1 : 100 d. 1 : 1000 โ Ans - b. 1 : 10 The mass of an electron is 9.1 โข 10^-31 kg and that of a proton is 1.7 โข 10^-27 kg. Which one of the following is the difference in the order of magnitude of the masses of the electron and the proton? a. 10. b. 7. c. 5. d. 3 โ Ans - d. 3 The volume of the Earth is approximately 10^12 km^3 and the volume of a grain of sand is approximately 1 mm^3. The order of magnitude of the number of grains of sand that can fit in the volume of the Earth is a. 10^ b. 10^ c. 10^ d. 10^30 โ Ans - d. 10^ The time interval between human heartbeats is of the order of a. 10^02 s b. 10^-1 s c. 10^0 s d. 10^1 s โ Ans - c. 10^0 s
