Education Exams (Educ Gen Sci) – Page 7

#120. 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
Answer: vertically
#121. What should a good diode tested with an ohmmeter indicate?
A High resistance when forward or reverse biased.
B High resistance when reverse biased and low resistance when forward biased.
C Low resistance when forward or reversed biased.
D High resistance when forward biased and low resistance when forward biased.
Answer: High resistance when reverse biased and low resistance when forward biased.
#122. Vacuum tubes in a radio transmitter are used to ________.
A provide lighting inside the studio
B record programs
C provide DC supply
D generate high power radio waves
Answer: generate high power radio waves
#123. Which material is the usual component of an anode?
A Copper
B Carbon
C Aluminum
D Nickel
Answer: Aluminum
#124. 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 Convection
B Radiation
C Thermal expansion
D Conduction
Answer: Conduction
#125. 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
Answer: Radiation
#126. Which process of heat transfer happens by the movement of mass from one place to another?
A Conduction
B Convection
C Induction
D Radiation
Answer: Convection
#127. When work is done by a system, what happens to its temperature assuming that no heat is added to it?
A increases
B decreases
C remains the same
D none of these
Answer: decreases
#128. 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
Answer: Zeroth Law of Thermodynamics
#129. What happens in an adiabatic process?
A The pressure of the system remain constant
B The temperature of the system remains constant
C No heat enters or leaves the system
D The system does no work nor work is done on it.
Answer: No heat enters or leaves the system
#130. What thermodynamic process is involved in a closed car inside a hot garage?
A Adiabatic
B Isothermal
C Isobaric
D Isochoric
Answer: Isochoric
#131. 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 exothermic, negative
B endothermic, positive
C endothermic, negative
D exothermic, positive
Answer: endothermic, positive
#132. Which of the following statements is FALSE?
A The total entropy of the universe increases in any spontaneous process.
B Any irreversible process results in an overall increase in entropy.
C 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.
D Entropy increases with the number of micro-states of the system.
Answer: 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.
#133. During a refrigeration cycle, heat is rejected by the refrigerant in a ________.
A expansion valve
B evaporator
C condenser
D compressor
Answer: condenser
#134. 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 high temperature body and delivers it to a low temperature body.
D Removes heat from a low temperature body and delivers it to a high temperature body.
Answer: Removes heat from a high temperature body and delivers it to a low temperature body.
#135. Which of the following refrigerant has the maximum ozone depletion potential in the stratosphere?
A Ammonia
B Sulfur dioxide
C Fluorine
D Carbon dioxide
Answer: Fluorine
#136. Which phenomenon is BEST explained by the particle nature of light?
A Interference
B Photoelectric effect
C Doppler effect
D Polarization
Answer: Photoelectric effect
#137. According to the quantum theory of light, the energy of light is carried in discrete units called ________.
A photo electrons
B photons
C alpha particles
D protons
Answer: photons
#138. 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 consist mainly of empty space and have small, dense nuclei.
B Atoms can easily absorb and re-emit alpha particles.
C Alpha particles behave like waves when they interact with atom
D Atoms have most of their mass distributed loosely in an electron cloud
Answer: Atoms consist mainly of empty space and have small, dense nuclei.
#139. 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
Answer: emitted