In which of the following structures coordination
Question: In which of the following structures coordination number for cations and anions in the packed structure will be same? (i) Clion form fcc lattice and Na+ ions occupy all octahedral voids of the unit cell. (ii) Ca2+ ions form fcc lattice and F- ions occupy all the eight tetrahedral voids of the unit cell. (iii) O2 ions form fcc lattice and Na+ions occupy all the eight tetrahedral voids of the unit cell. (iv) S2 ions form fcc lattice and Zn2+ ions go into alternate tetrahedral voids of th...
Read More →The probability that a person will get an electrification contract ia (2/5) and the probability that he will not get a plumbing contract is (4/7).
Question: The probability that a person will get an electrification contract ia (2/5) and the probability that he will not get a plumbing contract is (4/7). If the probability of getting at least one contract is (2/3), what is the probability that he will get both? Solution: Let A denote the event that a person will get electrification contract and B denote the event that the person will get a plumbing contract Given : $\mathrm{P}(\mathrm{A})=\frac{2}{5}, \mathrm{P}($ not $\mathrm{B})=\mathrm{P}...
Read More →Which of the following statement is not true
Question: Which of the following statement is not true about the hexagonal close packing? (i) The coordination number is 12. (ii) It has 74% packing efficiency. (iii) Tetrahedral voids of the second layer are covered by the spheres of the third layer. (iv) In this arrangement spheres of the fourth layer are exactly aligned with those of the first layer. Solution: Option (iv)In this arrangement spheres of the fourth layer are exactly aligned with those of the first layeris the answer....
Read More →The percentage of empty space in a body centred
Question: The percentage of empty space in a body centred cubic arrangement is ________. (i) 74 (ii) 68 (iii) 32 (iv) 26 Solution: Option (iii)32 is the answer....
Read More →In which pair most efficient packing is present?
Question: In which pair most efficient packing is present? (i) hcp and bcc (ii) hcp and ccp (iii) bcc and up (iv) bcc and simple cubic cell Solution: Option (ii)hcp and ccp is the answer....
Read More →Which of the following point defects are shown
Question: Which of the following point defects are shown by AgBr(s) crystals? (A) Schottky defect (B) Frenkel defect (C) Metal excess defect (D) Metal deficiency defect (i) (A) and (B) (ii) (C) and (D) (iii) (A) and (C) (iv) (B) and (D) Solution: Option (i)(A) and (B)is the answer....
Read More →The total number of tetrahedral voids
Question: The total number of tetrahedral voids in the face-centred unit cell is __________. (i) 6 (ii) 8 (iii) 10 (iv) 12 Solution: Option (ii)8 is the answer...
Read More →Evaluate the following integrals:
Question: Evaluate the following integrals: $\int \frac{1}{4 \cos x-1} d x$ Solution: Given I $=\int \frac{1}{4 \cos x-1} d x$ We know that $\cos x=\frac{1-\tan ^{2} \frac{x}{2}}{1+\tan ^{2} \frac{x}{2}}$ $\Rightarrow \int \frac{1}{-1+4 \cos x} d x=\int \frac{1}{-1+4\left(\frac{1-\tan ^{2} \frac{x}{2}}{1+\tan ^{2} \frac{x}{2}}\right)} d x$ $=\int \frac{1+\tan ^{2} \frac{x}{2}}{-1\left(1+\tan ^{2} \frac{x}{2}\right)+4\left(1-\tan ^{2} \frac{x}{2}\right)} d x$ Replacing $1+\tan ^{2} x / 2$ in nume...
Read More →The probability that Hemant passes in English is (2/3), and the probability that he passes in Hindi is (5/9).
Question: The probability that Hemant passes in English is (2/3), and the probability that he passes in Hindi is (5/9). If the probability of his passing both the subjects is (2/5), find the probability that he will pass in at least one of these subjects. Solution: let A denot the event that Hemant passes in english and B denote the event that hemant passes in hindi . Given : $P(A)=\frac{2}{3}, P(B)=\frac{5}{9}, P(A$ and $B)=\frac{2}{5}$ To find : Probability that he will pass in at least one of...
Read More →To get a n-type semiconductor from silicon,
Question: To get a n-type semiconductor from silicon, it should be doped with a substance with valence__________. (i) 2 (ii) 1 (iii) 3 (iv) 5 Solution: Option (iv)5 is the answer....
Read More →Which of the following is true about the charge
Question: Which of the following is true about the charge acquired by p-type semiconductors? (i) positive (ii) neutral (iii) negative (iv) depends on the concentration of p impurity Solution: Option (ii)neutral is the answer...
Read More →Schottky defect is observed in crystals
Question: Schottky defect is observed in crystals when __________. (i) some cations move from their lattice site to interstitial sites. (ii) the equal number of cations and anions are missing from the lattice. (iii) some lattice sites are occupied by electrons. (iv) some impurity is present in the lattice. Solution: Option (ii)the equal number of cations and anions are missing from the lattice is the answer....
Read More →Cations are present in the interstitial
Question: Cations are present in the interstitial sites in __________. (i)Frenkel defect (ii) Schottky defect (iii) Vacancy defect (iv) Metal deficiency defect Solution: Option (i)Frenkel defectis the answer....
Read More →In class, 30% of the students offered mathematics 20% offered chemistry and 10% offered both.
Question: In class, 30% of the students offered mathematics 20% offered chemistry and 10% offered both. If a student is selected at random, find the probability that he has offered mathematics or chemistry. Solution: Given: Math students = 30% Chemistry Students $=20 \%$ Math \ Chemistry both $=10 \%$ To Find: P(Math or Chemistry) Now, $\mathrm{P}$ (Math) $=30 \%=\frac{30}{100}=0.30$ $\mathrm{P}($ Chemistry $)=20 \%=\frac{20}{100}=0.20$ $\mathrm{P}($ Math $\cap$ Chemistry $)=10 \%=\frac{10}{100}...
Read More →Graphite cannot be classified as __________.
Question: Graphite cannot be classified as __________. (i) conducting solid (ii) network solid (iii) covalent solid (iv) ionic solid Solution: Option (iv)ionic solid is the answer....
Read More →Evaluate the following integrals:
Question: Evaluate the following integrals: $\int \frac{1}{1-2 \sin x} d x$ Solution: Given $I=\int \frac{1}{1-2 \sin x} d x$ We know that $\sin x=\frac{2 \tan \frac{x}{2}}{1+\tan \frac{x}{2}}$ $\Rightarrow \int \frac{1}{1-2 \sin x} d x=\int \frac{1}{1-2\left(\frac{2 \tan \frac{x}{2}}{1+\tan \frac{2}{2}}\right)} d x$ $=\int \frac{1+\tan ^{2} \frac{x}{2}}{1\left(1+\tan ^{2} \frac{x}{2}\right)-2\left(2 \tan \frac{x}{2}\right)} d x$ Replacing $1+\tan ^{2} x / 2$ in numerator by $\sec ^{2} x / 2$, $...
Read More →The lattice site in a pure crystal cannot
Question: The lattice site in a pure crystal cannot be occupied by _________. (i) molecule (ii) ion (iii) electron (iv) atom Solution: Option (iii)electron is the answer....
Read More →Which of the following oxides shows electrical
Question: Which of the following oxides shows electrical properties like metals? (i) SiO2 (ii) MgO (iii) SO2(s) (iv) CrO2 Solution: Option (iv)CrO2is the answer....
Read More →Two dice are thrown together.
Question: Two dice are thrown together. What is the probability that the sum of the numbers on the two faces is neither divisible by 3 nor by 4. Solution: Given: Two dice are thrown together. Sample Space: $(1,1)(1,2)(1,3)(1,4)(1,5)(1,6)$ $(2,1)(2,2)(2,3)(2,4)(2,5)(2,6)$ $(3,1)(3,2)(3,3)(3,4)(3,5)(3,6)$ $(4,1)(4,2)(4,3)(4,4)(4,5)(4,6)$ $(5,1)(5,2)(5,3)(5,4)(5,5)(5,6)$ $(6,1)(6,2)(6,3)(6,4)(6,5)(6,6)$ To Find: $\mathrm{P}$ (sum of faces neither divisible by 3 nor by 4 ) Sum $=\{2,3,4,5,6,7,8,9,10...
Read More →Which of the following oxides behaves
Question: Which of the following oxides behaves as conductor or insulator depending upon temperature? (i) TiO (ii) SiO2 (iii) TiO3 (iv) MgO Solution: Option (iii)TiO3 is the answer....
Read More →Graphite is a good conductor of electricity
Question: Graphite is a good conductor of electricity due to the presence of __________. (i) lone pair of electrons (ii) free valence electrons (iii) cations (iv) anions Solution: Option (ii)free valence electrons is the answer....
Read More →Which of the following is not the characteristic
Question: Which of the following is not the characteristic of ionic solids? (i) A very low value of electrical conductivity in the molten state. (ii) Brittle nature. (iii) Very strong forces of interactions. (iv) Anisotropic nature. Solution: Option (i)A very low value of electrical conductivity in the molten state is the answer....
Read More →Which of the following solids is not an
Question: Which of the following solids is not an electrical conductor? (A) Mg (s) (B) TiO (s) (C) I2 (s) (D) H2O (s) (i) (A) only (ii) (B) Only (iii) (C) and (D) (iv) (B), (C) and (D) Solution: Option (iii) (C) and (D) is the answer....
Read More →Which of the following is a network solid?
Question: Which of the following is a network solid? (i) SO2 (Solid) (ii) I2 (iii) Diamond (iv) H2O (Ice) Solution: Option (iii)Diamond is the answer....
Read More →Two dice are tossed once.
Question: Two dice are tossed once. Find the probability of getting an even number on the first die or a total of 8. Solution: Given : two dice are tossed once To find : Probability of getting an even number on the first die or a total 8. The formula used : Probability = $P(A$ or $B)=P(A)+P(B)-P(A$ and $B)$ A die is numbered from 1 to 6 When two dice are tossed once, total number of outcomes $=6^{2}=36$ Let $A$ denote the event of getting an even number on the first die and $B$ denote the event ...
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