PHYSICAL SCIENCE (3)

 1)  What is a closed, continuous path through which electrons can flow?

a.  Charge

b.  Circuit

c.  Resistor

d.  Voltage

 

2)  What will be your charge if you scrape electrons from your feet while scuffing across the rug?

a.  Negative

b.  Neutral

c.  Positive

d.  Not enough information given

 

3)  How will your force change if the distance between the two charged spheres is doubled?

a.  The force is doubled

b.  The force is tripled

c.  The force is quadrupled

d.  The force is multiplied eight times

 

4)  A 6 ohm and 12 ohm resistors are connected in parallel with each other to a battery. Which of the following is TRUE?

a.  More current will flow through the 20 ohm resistor.

b.  The current flowing through the resistors is the same.

c.  The resistor values must be equal for the circuit to work.

d.  The potential difference across the two resistors is the same.

 

5)  A new 1.5 V dry cell furnishes 30 A when short circuited. Find the internal resistance of the cell.

a.  0.05 ohm

b.  0.10 ohm

c.  1.5 ohm

d.  30 ohm

 

6)  If three identical lamps are connected in parallel to a 6 V dry cell, what is the voltage drop across each lamp?

a.  2 V

b.  3 V

c.  6 V

d.  18 V

 

7)  Which of the following describes an electric current?

a.  Regulates the movement of electric charge.

b.  The opposition a material offers to the electron flow.

c.  The electric pressure that causes charged particles to flow.

d.  The movement of charged particles in a specific direction.

 

8. A 10 W bulb and a 20 W bulb are connected in a series circuit. Which bulb has the more current flowing in it?

a.  The 10 W bulb

b.  The 20 W bulb

c.  Both bulbs have the same current

d.  Cannot be determined

 

9)  Which of the following are characteristics of a series circuit?

I.  The current that flows through each resistance is the same as the total current throughout the circuit.

II.  The sum of all the individual voltage drops is the same as the applied voltage.

III.  The reciprocal of the total resistance is equal to the sum of the reciprocals of the separate resistances.

IV.  The voltage drop in each resistance is the same as the magnitude of the applied voltage.

a.  I and II

b.  I and III

c.  III and IV

d.  I, II and III

 

10)  Which states that the sum of all potential rises and potential drops in any loop (closed circuit) is zero?

a.  Coulomb's Law

b.  Kirchoff's Law

c.  Law of Electrolysis

d.  Ohm's Law

 

11)  A television and an electric fan are connected in parallel top a 220 V line. The current in the television is 8 A and in the electric fan is 3 A. What is the current flowing in the line?

a.  2.67 A

b.  5 A

c.  11 A

d.  24 A

 

12) What happens to current if resistance increases?

a.  Decreases

b.  Increases

c.  No change

d.  Cannot be determined

 

13)  Which of the following statements DOES NOT represent Ohm's Law?

a.  current/potential difference = constant

b.  potential difference/current = constant

c.  potential difference = current x resistance

d.  current = resistance x potential difference

 

14)  What is the resistance of an electric bulb drawing 1.2 A current and 6.0 V?

a.  0.2 ohm

b.  0.5 ohm

c.  2 ohm

d.  5 ohm

 

15)  What happens to the current-carrying ability of a wire as temperature increases?

a.  There is no change.

b.  The wire can't carry any current.

c.  The wire can carry more current.

d.  The wire can carry less current.

 

16)  A 300 W at 220 V TV set is used at an average of 4 hours a day for 30 days. If the electrical energy costs P1.60 per kilowatt-hour, how much is the energy cost?

a.  P5.76

b.  P22.50

c.  P57.60

d.  P225.00

 

17)  Electromagnetic radiation can be used for wireless communications. Which of the following can be used to transmit signals such as mobile phone calls?

a.  Infrared

b.  Gamma

c.  Microwaves

d.  Radiowaves

 

18)  Which statement about the North-magnetic pole of the Earth is TRUE?

a.  Its location never changes.

b.  It corresponds to the N-pole of a bar magnet.

c.  It corresponds to the S-pole of a bar magnet.

d.  It is at the same location as the geographic north pole of the Earth.

 

19)  An iron nail can be turned into a temporary magnet if it is held in a strong magnetic field. Which method of magnetization is this?

a.  Charging

b.  Conduction

c.  Induction

d.  Saturation

 

20)  Which of the following factors affect the size of the induced current in a coil?

I.  Number of turns in the coil

II.  Size of the inducing field

III.  Direction of the windings in the coil

IV.  Resistance of the wire in the coil

a.  I and II

b.  III and IV

c.  I, II and III

d.  I, II and IV

 

21)  To use the right hand rule to predict the direction of an induced current in a coil, your thumb must point ________.

a.  to the direction of the motion of the wire

b.  to the N-pole of the induced magnetic field

c.  in the direction of the induced current

d.  in the direction of the inducing field

 

22)  When a bar magnet is inserted into a coil, a current of 12.0 A is induced into the coil. If four magnets of the same type are inserted into the coil at the same time, what would be the induced current?

a.  3 A

b.  4 A

c.  12 A

d.  48 A

 

23)  What is the direction of a magnetic field within a magnet?

a.  from north to south

b.  from south to north

c.  from to back

d.  back to front

 

24)  Which is the induced voltage across a stationary conductor in a stationary magnetic field?

a.  decreased

b.  increased

c.  zero

d.  reversed in polarity

 

25)  What is the magnetomotive force (mmf) of a wire with 8 turns carrying 3 A of current?

a.  2.67

b.  24

c.  240

d.  2,400

 

26)  A coil of wire is placed in a changing magnetic field. If the number of turns in the coil is decreased, what will happen to the voltage induced across the coil?

a.  remain constant

b.  be excessive

c.  decrased

d.  increased

 

27)  Which of the following is TRUE about the frequency and velocity of electromagnetic waves?

a.  Frequency and wavelength are interdependent of each other

b.  As frequency increases, wavelength decreases

c.  As frequency increases, wavelength increases

d.  Frequency is constant for all wavelengths

 

28)  Which of the following correctly lists electromagnetic waves in order from longest to shortest wavelength?

a.  television, infrared, visible light, x-rays

b.  gamma rays, ultraviolet, infrared, microwaves

c.  radiowaves, infrared, gamma rays, ultraviolet

d.  microwaves, ultraviolet, visible light, gamma rays

 

 

29)  An electromagnetic wave is radiated by a straight wire antenna that is oriented vertically. What should be the orientation of a straight wire receiving antenna?

a.  diagonally

b.  vertically

c.  horizontally and in a direction parallel to the wave's direction of motion

d.  horizontally and in a direction perpendicular to the wave's direction of motion

 

30)  What should a good diode tested with an ohmmeter indicate?

a.  High resistance when forward or reverse biased.

b.  Low resistance when forward or reversed biased.

c.  High resistance when reverse biased and low resistance when forward biased.

d.  High resistance when forward biased and low resistance when forward biased.

 

31)  Vacuum tubes in a radio transmitter are used to ________.

a.  record programs

b.  provide DC supply

c.  generate high power radio waves

d.  provide lighting inside the studio

 

32)  Which material is the usual component of an anode?

a.  Aluminum

b.  Carbon

c.  Copper

d.  Nickel

 

33)  A metal spoon is placed in a cup filled with hot coffee. After some time, the exposed end of the spoon becomes hot even without a direct contact with the liquid. What explains this phenomenon?

a.  Conduction

b.  Convection

c.  Radiation

d.  Thermal expansion

 

34)  Which causes the warmth that you feel when you place your finger at the side of the flame of a burning candle?

a.  Conduction

b.  Convection

c.  Radiation

d.  Not enough information given

 

35)  Which process of heat transfer happens by the movement of mass from one place to another?

a.  Conduction

b.  Convection

c.  Induction

d.  Radiation

 

36)  When work is done by a system, what happens to its temperature assuming that no heat is added to it?

a.  decreases

b.  increases

c.  remains the same

d.  none of these

 

37)  Which states that "when two systems are in thermal equilibrium with a third system, then they are in thermal equilibrium with each other?

a.  Zeroth Law of Thermodynamics

b.  First Law of Thermodynamics

c.  Second Law of Thermodynamics

d.  Mechanical Equivalent of Heat

 

38)  What happens in an adiabatic process?

a.  No heat eneters or leaves the system

b.  The pressure of the system remain constant

c.  The temperature of the system remains constant

d.  The system does no work nor work is done on it.

 

39)  What thermodynamic process is involved in a closed car inside a hot garage?

a.  Adiabatic

b.  Isobaric

c.  Isochoric

d.  Isothermal

 

40)  Consider the thermal energy transfer during a chemical process. When heat is transferred to the system, the process is said to be ________ and the sign of H is ________.

a.  endothermic, positive

b.  endothermic, negative

c.  exothermic, positive

d.  exothermic, negative

 

41)  Which of the following statements is FALSE?

a.  Entropy increases with the number of microstates of the system.

b.  Any irreversible process results in an overall increase in entropy.

c.  The total entropy of the universe increases in any spontaneous process.

d.  The change in entropy in a system depends on the initial and final states of the system and the path taken from one state to the other.

 

42)  During a refrigeration cycle, heat is rejected by the refrigerant in a ________.

a.  compressor

b.  condenser

c.  evaporator

d.  expansion valve

 

43)  Which of the following CORRECTLY describes a refrigeration system?

a.  Rejects energy to a low temperature body.

b.  Rejects energy to a high temperature body.

c.  Removes heat from a low temperature body and delivers it to a high temperature body.

d.  Removes heat from a high temperature body and delivers it to a low temperature body.

 

44)  Which of the following refrigerant has the maximum ozone depletion potential in the stratosphere?

a.  Ammonia

b.  Carbon dioxide

c.  Fluorine

d.  Sulfur dioxide

 

45)  Which phenomenon is BEST explained by the particle nature of light?

a.  Doppler effect

b.  Interference

c.  Photoelectric effect

d.  Polarization

 

46)  According to the quantum theory of light, the energy of light is carried in discrete units called ________.

a.  alpha particles

b.  photoelectrons

c.  photons

d.  protons

 

47)  Rutherford observed that most of the alpha particles directed at a metallic foil appear to pass through unhindered, with only a few deflected at large angles. What did he conclude?

a.  Atoms can easily absorb and re-emit aplha particles.

b.  Atoms consist mainly of empty space and have small, dense nuclei.

c.  Alpha particles behave like waves when they interact with atom.

d.  Atoms have most of their mass distributed loosely in an electron cloud.

 

48)  When an electron changes from a higher energy to a lower energy state within an atom, a quantum of energy is ________.

a.  absorbed

b.  emitted

c.  fissioned

d.  fused

 

49)  When does nuclear fission occur?

a.  When we cut nuclei into two with a very small cutting device.

b.  When one nucleus bumps into another causing a chain reaction.

c.  When a nucleus divides spontaneously, with no apparent reason.

d.  When electrical forces inside a nucleus overpower forces.

 

50)  When does nuclear fusion release energy?

a.  When uranium emits a neutron

b.  When heavy ions fuse together

c.  When very light nuclei fuse together

d.  When uranium splits into two fragments


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