Free Scientific Reasoning MCQs with Answers

101. A bar magnet is placed stationary next to a conducting coil, as shown below.What do we observe in the coil?Choose 1 answer:

• A. The magnet feels a force due to the coil.
• B. A current flows from A to B.
• C. A current flows from B to A.
• D. Nothing happens.

Explanation: If the magnet is brought near the coil, the field associated with the coil changes and hence the magnetic field changes. This change in magnetic flux induces current in the coil. This can be done by bringing magnet to the coil, or bringing coil to the magnet. However in the case mentioned there is no change in motion or flux thus nothing happens.

102. The following is a diagram of a sarcomere.How do the labelled parts change during muscle contraction?

• A. "D" shortens
• B. "C" stays the same
• C. "B" shortens
• D. Two "A"s move closer together

Explanation: A sarcomere is defined as the distance between two consecutive Z discs or Z lines; when a muscle contracts, the distance between the Z discs is reduced. The H zone-the central region of the A zone-contains only thick filaments and is shortened during contraction. This is correct.D is the sarcomere, a represents Z line, b represents A zone, c represents z disc.

103. For fixed values of wavelength and x, when the slit width was doubled, the distance from the center of the brightest band in the pattern to the center of one of the 2 adjacent dark bands:

• A. Was doubled.
• B. Was halved.
• C. Remained unchanged.
• D. Varied with no general trend.

Explanation: Keeping the wavelength and x constant in study 1, when slit length is doubled, y is halved. Therefore, this option is the correct answer.

104. The diagram below represents a process that occurs during human reproduction.What is the result of this process (found on the right side of the arrow)?

• A. A blastocyst containing half of the genetic information
• B. An embryo containing half of the genetic information
• C. A gamete containing a complete set of the genetic information
• D. A zygote containing a complete set of genetic information

Explanation: A zygote is formed when a sperm fertilises an ovum. It contains a complete set of genetic information, with half contributed by the sperm and half by the ovum. The zygote is the initial stage of development from which an embryo develops.

105. Tollen's reagent is an oxidation agent. What are the products of Tollen's reagent reaction with the following molecule?

• A. Propanol and Ag+
• B. Propanoic acid and Ag+
• C. Propanol and Ag
• D. Propanoic acid and Ag

Explanation: It is correct as explained, in the Silver mirror test the product formed is a carboxylic acid and metallic silver. The compound shown is propionaldehyde or propanal hence it forms propanoic acid. Oxidizing agents are substances that become reduced after oxidation of another molecule. Oxidation of an aldehyde will yield a carboxylic acid. The propanal is oxidized to a carboxylic acid and the silver ion is reduced to metallic silver.

106. The figure below is a pedigree that shows the inheritance of a trait, Trait G, in a family. The presence of Trait G in an individual is determined entirely by Gene G. Gene G has 2 alleles: G, which is dominant, and g, which is recessive.Each individual represented in the pedigree was assigned a number (shown below the symbol for the individual) for reference. Scientists determined that the Gene G genotype of Individual 20 is Gg and that the Gene G genotype of Individual 21 is gg. Based on this information, the scientists concluded that Trait G is a dominant trait.Based on the figure, the 2 individuals in which of the following pairs most likely have the greatest genetic similarity across their genomes?

• A. Individual 3 and Individual 4
• B. Individual 12 and Individual 13
• C. Individual 16 and Individual 24
• D. Individual 18 and Individual 21

Explanation: The best answer is B. In order to answer this item, the examinee must know that the more closely related two individuals are to each other, the greater the genetic similarity is likely to be. According to the figure, Individuals 12 and 13 are sisters and would likely have the greatest genetic similarity.

107. Passage IThe figure below is a pedigree that shows the inheritance of a trait, Trait G, in a family. The presence of Trait G in an individual is determined entirely by Gene G. Gene G has 2 alleles: G, which is dominant, and g, which is recessive.Each individual represented in the pedigree was assigned a number (shown below the symbol for the individual) for reference. Scientists determined that the Gene G genotype of Individual 20 is gg and that the Gene G genotype of Individual 21 is Gg. Based on this information, the scientists concluded that Trait G is a recessive trait.Suppose that Individual 23 and Individual 24 have 4 biological children. Based on the figure, how many of the children, if any, have Trait G?

• A. 0
• B. 1
• C. 3
• D. 4

Explanation: The best answer is D. In order to answer this item, the examinee must know how to work a genetic cross. According to the figure, both Individuals 23 and 24 have Trait G. According to the passage, Trait G is recessive. It follows that Individuals 23 and 24 both have the gg genotype and that all their children will also have the gg genotype. All their children will therefore have Trait G.

108. Passage IThe figure below is a pedigree that shows the inheritance of a trait, Trait G, in a family. The presence of Trait G in an individual is determined entirely by Gene G. Gene G has 2 alleles: G, which is dominant, and g, which is recessive.Each individual represented in the pedigree was assigned a number (shown below the symbol for the individual) for reference. Scientists determined that the Gene G genotype of Individual 20 is gg and that the Gene G genotype of Individual 21 is Gg. Based on this information, the scientists concluded that Trait G is a recessive trait.According to the figure, how many of the grand- children of Individual 1 and Individual 2, if any, have Trait G?

• A. 0
• B. 1
• C. 2
• D. 7

Explanation: The best answer is C. According to the figure, the grandchildren of Individuals 1 and 2 are Individuals 10, 11, 12, 13, 15, 16, and 17. According to the key for the figure, a black circle and black square represent individuals with Trait G. Of the grandchildren, only Individuals 10 and 16 have Trait G.

109. Which of the following compounds is the most acidic?Choose 1 answer:

• A. Butane
• B. 2-butanone
• C. 1-butanone
• D. Butanol

Explanation: Two of the three compounds have charge on carbon atoms and third have charge on oxygen atoms, there is not much size difference between the two but being a stronger electronegative atom oxygen can hold that negative charge more effectively than carbon atom hence butanol will be most acidic.

110. To the right are drawings of a wide and a narrow cylinder. The cylinders have equally spaced marks on them. Water is poured into the wide cylinder up to the 4th mark (see A). This water rises to the 6th mark when poured into the narrow cylinder (see B).Both cylinders are emptied (not shown) and water is poured into the narrow cylinder up to the 11th mark. How high would this water rise if it were poured into the empty wide cylinder?

• A. To about 7 1/2
• B. To about 7 1/3
• C. To about 8
• D. To about 9
• E. None of these answers is correct

Explanation: The height of the water when poured into the empty wide cylinder is;Option b; To the 7¹/₃ markFormula for volume of a cylinder is;V = πr²h where;r is radiush is heightWe are told that water is poured into the wide cylinder up to the 4th mark. Thus, for the wide cylinder, h = 4. Thus;V_wide = 4πR²Similarly, we are told that water is poured into the narrow cylinder up to the 6th mark. Thus, for the narrow cylinder, h = 6. Thus;V_narrow = 6πr²Now, the volume of the water will be the same since it was the same quantity that was poured. Thus;V_wide = V_narrow4πR² = 6πr²⇒ R²/r² = 6/4simplifies to get; R²/r² = ³/₂Now both cylinders were emptied and water poured rises to the 11th mark for the narrow cylinder. Thus;πR²H = 11πr²R²/r² = 11/HEarlier, we saw that R²/r² = ³/₂. Thus;11/H = ³/₂H = 22/3H = 7¹/₃