CDS I - General Knowledge Previous Year Question Paper 2017 - CDS MCQ

Polynucleotide is a molecule is a biopolymer composed of 13 or more nucleotide monomers covalently bonded in a chain.

Following are major reasons for the transmission of HIV infection:

• Sexual intercourse through vaginal, rectal, or penile tissues.
• Direct injection with HIV-contaminated drugs, needles, syringes, blood or blood products.
• From HIV-infected mother to foetus in uterus, through intrapartum inoculation from mother to infant or during breast-feeding.

In human body, the cell growth and differentiation are highly controlled and regulated, but in cancer cells there is breakdown of these regulatory mechanisms leading to formation of benign and malignant tumours.

• Most viruses that infect plants possess single-stranded RNA.
• DNA- Deoxyribonucleic acid is the hereditary material in humans and almost all other organisms.
• RNA-Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation, and expression of genes.

• When a piece of pure silicon is doped with aluminium, then the doped silicon piece will become p-type.
• Doping is the process of adding impurities to intrinsic semiconductors to alter their properties. Normally trivalent and pentavalent elements are used to dope Silicon and Germanium.

• Power dissipated across a parallel combination = Sum of the power of each component (same as with series circuits)
• Power dissipated = V²/R

In a parallel circuit, the voltage across each of the components remains the same.
So, Power dissipated in the second circuit will be 3P.

• Semiconductor- A substance that has a conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects.
• Examples of Semiconductor Materials - Germanium, Seleniumand Silicon etc.

• Parallel Plate Capacitors are the type of capacitors which are formed by arrangement of two or more parallel conductive plates which are not connected or touching each other but are electrically separated either by air or by some form of a good insulating material.
• Capacitance is directly proportional to value of dielectric constant. Hence Capacitance will be 7C.

• For a ring the centre of mass lies outside the body i.e. at the centre of curvature of the ring.
• Centre of mass of a distribution of mass in space is the unique point where the weighted relative position of the distributed mass sums to zero, or the point where if a force is applied it moves in the direction of the force without rotating.
• The centre of mass may be located outside the physical body in case of hollow or open-shaped objects.

• Heating of platinum crucible is a physical change as in this process formation of new substance do not take place and the change is reversible.
• Physical change is the change from one phase of matter (solid, liquid, or gas) to another and the substance is not altered.
• Chemical change is a process in which a substance is permanently altered.

• The pH value of a sample of multiple-distilled water is very near to seven.
• pH stands for power of hydrogen, which is a measurement of the hydrogen ion concentration in the body.

Atomic number is the most characteristic property of an element.

• J. J. Thomson, who discovered the electron in 1897, proposed the plum pudding model of the atom in 1904 before the discovery of the atomic nucleus in order to include the electron in the atomic model.
• He proposed that atoms have structure like a plum pudding, with tiny, negatively charged electrons embedded in a positively charged substrate. This was later shown to be incorrect.

Number of atoms = No: of moles × Avogadro no:
Given mass of Na (Sodium) = 46 g
Molar mass of Na = 23 g
No of moles = Given mass ÷ Molar mass
= 46 ÷ 23
= 2 moles
∴ Number of atoms = 2 moles × N (N = Avogadro constant)
= 2N

• For the purpose of Census 2011-A person aged seven and above who can both read and write with understanding in any language is treated as a literate.
• Census 2011: Total population: 1,210,193,422
• Literacy rate: 74.04%

• Loktak Lake is the largest freshwater lake in Northeast India and is famous for the phumdis (a series of floating islands) floating over it.
• The lake is located near Moirang town in Manipur state.

A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. The system of streams on a dissected volcano cone is a radial drainage pattern.

In mammalian heart the heartbeat originates from Sinoatrial node. Mammalian circulatory system is divided into three circuits: the systemic circuit, the pulmonary circuit, and the coronary circuit.

• Plant Growth Regulators are defined as small, simple chemicals produced naturally by plants to regulate their growth and development.
• Plant Growth Regulators can be of a diverse chemical composition such as Indole compounds, adenine derivatives, carotenoids and terpenes
• Plant Growth Promoters – They promote cell division, cell enlargement, flowering, fruiting and seed formation.
• Examples are auxins, gibberellins and cytokinins.

Visible light - that which is detectable by the human eye - consists of wavelengths ranging from approximately 750 nanometres (7.50 x 10^-7 m) down to 380 nanometres (3.80 x 10^-7 m).

Wire A
Length = l
Radius = r
Resistance = ρ×l/πr²
Wire B
Length = l
Radius = 2r
Resistance = ρ×l/4πr²
Let R_p = Effective resistance of parallel combination
1/R_p= 1/R₁ + 1/R₂
1/R_p = 1/ρ × l/πr²+1/ρ × l/4πr²
1/R_p = ρl/5πr²
R_p = R/5

The capacitance of parallel plate capacitor depends upon

• The distance between the two plates of capacitor
• The area of parallel plates of capacitor
• Dielectric material

• The wavelength of X-ray photon is less than the wavelength of visible radiation photon.
• Both the photons have different energies.
• The speeds of both the photons in vacuum are same.
• The frequency of X-ray photon is higher than the frequency of visible radiation photon