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3) What type of control pins are needed in a microprocessor to regulate traffic on the bus, in order to prevent two devices from trying to use it at the same time?
(A) Bus control
(B) Interrupts
(C) Bus arbitration
(D) Status
Correct Answer - Option
(C)
Explanation :
The correct answer is:
Bus arbitration is the process used to regulate access to the system bus in a microprocessor. It ensures that multiple devices do not try to use the bus simultaneously, which could lead to conflicts or data corruption. Bus arbitration uses control signals to manage which device can use the bus at any given time, preventing two devices from accessing it at once.
Niels Bohr and Ernest Rutherford are credited with developing the model of atomic structure. Rutherford proposed the nuclear model of the atom, where most of the atom's mass and positive charge are concentrated in a small nucleus at the center. Bohr later modified this model by introducing the concept of quantized orbits for electrons, which helped explain atomic spectra. Together, their work laid the foundation for our current understanding of atomic structure.
5) Which among the following is a covalent compound ?
(A) Calcium chloride
(B) Magnesium fluoride
(C) Sodium chloride
(D) Carbon tetrachloride
Correct Answer - Option
(D)
Explanation :
Carbon tetrachloride (CCl₄) is a covalent compound because it is formed by the sharing of electrons between carbon and chlorine atoms. In covalent bonding, atoms share electrons to achieve a full outer electron shell.
The other compounds listed—Calcium chloride (CaCl₂), Magnesium fluoride (MgF₂), and Sodium chloride (NaCl)—are ionic compounds, where electrons are transferred from one atom to another, resulting in the formation of positively and negatively charged ions.
6) Atomic number of an atom gives the number of which of the following ?
(A) Electrons
(B) Protons
(C) Neutrons
(D) Neutrons and protons
Correct Answer - Option
(B)
Explanation :
The atomic number of an atom represents the number of protons in the nucleus of the atom. Since the number of protons also determines the element's identity on the periodic table, the atomic number is unique to each element. In a neutral atom, the number of electrons will also be equal to the number of protons, but the atomic number specifically refers to the protons.
(C) The number of electrons orbiting around the nucleus
(D) The number of nucleons in the nucleus
Correct Answer - Option
(C)
Explanation :
The chemical behavior of an atom depends primarily on the number of electrons in its outermost shell (also known as the valence electrons). These electrons are involved in chemical bonding and interactions with other atoms. The number of protons determines the element's identity, and the number of neutrons affects the isotope, but it is the electrons that dictate how an atom behaves chemically.
A matured mammalian erythrocyte (red blood cell) is unique in that it does not have a nucleus. During its maturation process, the nucleus is expelled to make more room for hemoglobin, which is essential for oxygen transport. This adaptation allows the red blood cell to carry more oxygen efficiently.
The other options:
Lymphocyte is a type of white blood cell with a nucleus.
Spermatozoan has a nucleus in its head, which contains genetic material.
Oocyte (egg cell) also has a nucleus.
9) Which of the following metals can displace copper from copper sulphate solution ?
(A) Platinum
(B) Mercury
(C) Iron
(D) Gold
Correct Answer - Option
(C)
Explanation :
Iron metal is more reactive than copper. Therefore, it can displace copper from copper sulphate (CuSO4) solution. Cu is less reactive than iron, therefore, cannot replace iron from iron sulphate (FeSO4).
International Workers' Day, also known as Labour Day or May Day, is celebrated on 1 May each year. It is a day to honor and celebrate the contributions of workers and to promote workers' rights around the world.
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