All (6)Unattempted (6)Skipped (0)Correct (0)Wrong (0)
Q.1
Based on: WBCS Prelims 2022
Which unit is defined as one radioactive decay per second in the International System of Units?
A.Becquerel
B.Temperature
C.Heat
D.Energy
Explanation
Why Correct: The becquerel (Bq) is the SI unit of radioactivity, precisely defined as one nuclear decay per second. It replaced the curie as the standard international unit. Distractor Analysis: Temperature is measured in kelvin, Celsius, or Fahrenheit. Heat uses joules or calories. Energy uses joules, ergs, or electronvolts. Takeaway: While the curie (Ci) is a historical unit equal to 3.7×10^10 decays per second, the becquerel is the modern SI unit for measuring radioactivity.
Answer or skip previous question to unlock.
Q.2
Based on: WBCS Prelims 2022
Which physical quantity is measured in units such as kelvin, Celsius, and Fahrenheit?
A.Temperature
B.Radioactivity
C.Heat
D.Energy
Explanation
Why Correct: Temperature quantifies the thermal state of a system, with kelvin as the SI base unit, Celsius for common use, and Fahrenheit in some regions. Distractor Analysis: Radioactivity uses becquerel or curie. Heat uses joules or calories. Energy uses joules, ergs, or electronvolts. Takeaway: Temperature is distinct from heat (energy transfer) and other physical quantities, with specific units for measurement.
Answer or skip previous question to unlock.
Q.3
Based on: WBCS Prelims 2022
What is the SI unit of heat?
A.Joule
B.Calorie
C.Watt
D.Kelvin
Explanation
Why Correct: The joule (J) is the SI unit of heat, representing the amount of energy transferred as heat. Distractor Analysis: The calorie is a non-SI unit of heat, defined as the energy needed to raise 1 gram of water by 1°C. The watt measures power, equal to one joule per second. The kelvin is the SI unit of thermodynamic temperature. Takeaway: The British thermal unit (BTU) is another common non-SI unit of heat, equal to about 1055 joules.
Answer or skip previous question to unlock.
Q.4
Based on: WBCS Prelims 2022
Who discovered radioactivity, leading to the naming of the unit 'curie'?
A.Marie Curie
B.Pierre Curie
C.Henri Becquerel
D.Ernest Rutherford
Explanation
Why Correct: Henri Becquerel discovered radioactivity in 1896 while studying uranium salts, for which he shared the 1903 Nobel Prize in Physics with the Curies. Distractor Analysis: Marie Curie and Pierre Curie conducted pioneering research on radioactivity and discovered radium and polonium. Ernest Rutherford studied radioactive decay and proposed the nuclear model of the atom. Takeaway: The SI unit of radioactivity, the becquerel (Bq), is named after Henri Becquerel and equals one decay per second.
Answer or skip previous question to unlock.
Q.5
Based on: WBCS Prelims 2022
Which international body is responsible for establishing and maintaining the International System of Units (SI)?
A.International Bureau of Weights and Measures (BIPM)
B.International Organization for Standardization (ISO)
C.General Conference on Weights and Measures (CGPM)
D.International Electrotechnical Commission (IEC)
Explanation
Why Correct: The General Conference on Weights and Measures (CGPM) establishes and maintains the International System of Units (SI). It is the supreme authority under the Metre Convention. Distractor Analysis: The International Bureau of Weights and Measures (BIPM) implements SI standards under CGPM direction. The International Organization for Standardization (ISO) develops voluntary international standards across many fields. The International Electrotechnical Commission (IEC) sets standards for electrical and electronic technologies. Takeaway: The Metre Convention of 1875 created the CGPM and BIPM, establishing the foundation for international measurement standards.
Answer or skip previous question to unlock.
Q.6
Based on: WBCS Prelims 2022
What was the immediate scientific consequence of Henri Becquerel's 1896 discovery of radioactivity?
A.Development of the first nuclear reactor
B.Proof of atomic nucleus existence
C.Discovery of X-rays by Wilhelm Röntgen
D.Recognition that some elements spontaneously emit radiation
Explanation
Why Correct: Henri Becquerel's discovery proved that uranium salts spontaneously emitted penetrating radiation without external energy. This revealed natural radioactivity as a new physical phenomenon. Distractor Analysis: The first nuclear reactor was built by Enrico Fermi in 1942. Ernest Rutherford proved atomic nucleus existence in 1911. Wilhelm Röntgen discovered X-rays in 1895, which actually inspired Becquerel's experiments.
Sign in to save progress
Sign in to Papersetters
Save your progress, unlock Smart Review, and track your performance.