Amorphous solid can also be called ________.
Question: Amorphous solid can also be called ________. (i) pseudo solids (ii) true solids (iii) supercooled liquids (iv) supercooled solids Solution: Option (i)pseudo solidsand (iii)supercooled liquids are the answers....
Read More →The number of tetrahedral voids per unit
Question: The number of tetrahedral voids per unit cell in NaCl crystal is ________. (i) 4 (ii) 8 (iii) twice the number of octahedral voids. (iv) four times the number of octahedral voids. Solution: Option (ii)8 and (iii)twice the number of octahedral voidsare the answers....
Read More →Evaluate the following integrals:
Question: Evaluate the following integrals: $\int \frac{1}{3+2 \sin x+\cos x} d x$ Solution: Given $I=\int \frac{1}{3+2 \sin x+\cos x} d x$ We know that $\sin x=\frac{2 \tan \frac{x}{2}}{1+\tan ^{2} \frac{x}{2}}$ and $\cos x=\frac{1-\tan \frac{2}{2}}{1+\tan \frac{2}{2}}$ $\Rightarrow \int \frac{1}{3+2 \sin x+\cos x} d x=\int \frac{1}{3+2\left(\frac{2 \tan \frac{x}{2}}{1+\tan ^{2} \frac{x}{2}}\right)+\frac{1-\tan ^{2} \frac{x}{2}}{1+\tan ^{2} \frac{x}{2}}} d x$ $=\int \frac{1+\tan ^{2} \frac{x}{2...
Read More →An excess of potassium ions makes KCl
Question: An excess of potassium ions makes KCl crystals appear violet or lilac in colour since ________. (i) some of the anionic sites are occupied by an unpaired electron. (ii) some of the anionic sites are occupied by a pair of electrons. (iii) there are vacancies at some anionic sites. (iv) F-centres are created which impart colour to the crystals. Solution: Option (i) and (iv) are the answers....
Read More →Which of the following statements are true about
Question: Which of the following statements are true about semiconductors? (i) Silicon doped with an electron-rich impurity is a p-type semiconductor. (ii) Silicon doped with an electron-rich impurity is an n-type semiconductor. (iii) Delocalised electrons increase the conductivity of doped silicon. (iv) An electron vacancy increases the conductivity of the n-type semiconductor. Solution: Option (ii) and (iii) are the answers....
Read More →Under the influence of the electric field,
Question: Under the influence of the electric field, which of the following statements is true about the movement of electrons and holes in a p-type semiconductor? (i) The electron will move towards the positively charged plate through electron holes. (ii) Holes will appear to be moving towards the negatively charged plate. (iii) Both electrons and holes appear to move towards the positively charged plate. (iv) Movement of electrons is not related to the movement of holes. Solution: Option (i) a...
Read More →Which of the following statements are
Question: Which of the following statements are true about metals? (i) Valence band overlaps with conduction band. (ii) The gap between the valence band and the conduction band is negligible. (iii) The gap between the valence band and the conduction band cannot be determined. (iv) Valence band may remain partially filled. Solution: Option (i), (ii) and (iv) are the answers....
Read More →Which of the following statements are not true?
Question: Which of the following statements are not true? (i) Vacancy defect results in a decrease in the density of the substance. (ii) Interstitial defects increase the density of the substance. (iii) Impurity defect does not affect the density of the substance. (iv) Frankel defect results in an increase in the density of the substance. Solution: Option (iii)Impurity defect does not affect the density of the substance and (iv)Frankel defect results in an increase in the density of the substanc...
Read More →The value of the magnetic moment is zero
Question: The value of the magnetic moment is zero in the case of antiferromagnetic substances because the domains ________. (i) get oriented in the direction of the applied magnetic field. (ii) get oriented opposite to the direction of the applied magnetic field. (iii) are oppositely oriented with respect to each other without the application of the magnetic field. (iv) cancel out each others magnetic moment. Solution: Option (iii) and (iv) are the answers....
Read More →Which of the following is not true about
Question: Which of the following is not true about the voids formed in 3-dimensional hexagonal close-packed structure? (i) A tetrahedral void is formed when a sphere of the second layer is present above triangular void in the first layer. (ii) All the triangular voids are not covered by the spheres of the second layer. (iii) Tetrahedral voids are formed when the triangular voids in the second layer lie above the triangular voids in the first layer and the triangular shapes of these voids do not ...
Read More →Which of the following represents correct
Question: Which of the following represents correct order of conductivity in solids? (i) metals insulators semiconductors (ii) metals insulators semiconductors (iii) metals semiconductors insulators = zero (iv) metals semiconductors insulators zero Solution: Option (i) metals insulators semiconductorsis the answer....
Read More →Evaluate the following integrals:
Question: Evaluate the following integrals: $\int \frac{1}{3+2 \sin x+\cos x} d x$ Solution: Given $I=\int \frac{1}{3+2 \sin x+\cos x} d x$ We know that $\sin x=\frac{2 \tan \frac{x}{2}}{1+\tan ^{2} \frac{x}{2}}$ and $\cos x=\frac{1-\tan ^{2} \frac{x}{2}}{1+\tan ^{2} \frac{x}{2}}$ $\Rightarrow \int \frac{1}{3+2 \sin x+\cos x} d x=\int \frac{1}{3+2\left(\frac{2 \tan \frac{x}{2}}{1+\tan ^{2} \frac{x}{2}}\right)+\frac{1-\tan ^{2} \frac{x}{2}}{1+\tan ^{2} \frac{x}{2}}} d x$ $=\int \frac{1+\tan ^{2} ...
Read More →The edge lengths of the unit cells in terms
Question: The edge lengths of the unit cells in terms of the radius of spheres constituting fcc,bcc and simple cubic unit cell are respectively________ (i) 22r, 4r/3, 2r (ii) 4r/3, 22r, 2r (iii) 2r, 22r, 4r/3 (iv) 2r, 4r/3, 22r Solution: Option (i)22r, 4r/3, 2ris the answer....
Read More →In a town of 6000 people, 1200 are over 50 years old, and 2000 are females.
Question: In a town of 6000 people, 1200 are over 50 years old, and 2000 are females. It is known that 30% of the females are over 50 years. What is the probability that a randomly chosen individual from the town is either female or over 50 years? Solution: let A denote the event that the chosen individual is female and B denote the event that the chosen individual is over 50 years old. Given : Town consists of 6000 people, 1200 are over 50 years old, and 2000 are females To find : Probability t...
Read More →In the cubic close packing,
Question: In the cubic close packing, the unit cell has ________. (i) 4 tetrahedral voids each of which is shared by four adjacent unit cells. (ii) 4 tetrahedral voids within the unit cell. (iii) 8 tetrahedral voids each of them which are shared by four adjacent unit cells. (iv) 8 tetrahedral voids within the unit cells. Solution: Option (iv) 8 tetrahedral voids within the unit cellsis the answer....
Read More →Which of the following defects is also
Question: Which of the following defects is also known as dislocation defect? (i) Frenkel defect (ii) Schottky defect (iii) Non-stoichiometric defect (iv) Simple interstitial defect Solution: Option (i)Frenkel defectis the answer....
Read More →The correct order of the packing efficiency
Question: The correct order of the packing efficiency in different types of unit cells is ________. (i) fcc bcc simple cubic (ii) fcc bcc simple cubic (iii) fcc bcc simple cubic (iv) bcc fcc simple cubic Solution: Option (ii) fcc bcc simple cubic is the answer....
Read More →A ferromagnetic substance becomes a permanent
Question: A ferromagnetic substance becomes a permanent magnet when it is placed in a magnetic field because ________. (i) all the domains get oriented in the direction of the magnetic field. (ii) all the domains get oriented in the direction opposite to the direction of the magnetic field. (iii) domains get oriented randomly. (iv) domains are not affected by the magnetic field. Solution: Option (i)all the domains get oriented in the direction of the magnetic field is the answer....
Read More →Which of the following is not true about
Question: Which of the following is not true about the ionic solids? (i) Bigger ions form the close-packed structure. (ii) Smaller ions occupy either the tetrahedral or the octahedral voids depending upon their size. (iii) Occupation of all the voids is not necessary. (iv) The fraction of octahedral or tetrahedral voids occupied depends upon the radii of the ions occupying the voids. Solution: Option (iv)The fraction of octahedral or tetrahedral voids occupied depends upon the radii of the ions ...
Read More →Which of the following statements is not true?
Question: Which of the following statements is not true? (i) Paramagnetic substances are weakly attracted by the magnetic field. (ii) Ferromagnetic substances cannot be magnetised permanently. (iii) The domains in antiferromagnetic substances are oppositely oriented with respect to each other. (iv) The pairing of electrons cancels their magnetic moment in the diamagnetic Solution: Option (ii)Ferromagnetic substances cannot be magnetised permanently is the answer....
Read More →The probability that a patient visiting a denist will have a tooth extracted is 0.06, the probability
Question: The probability that a patient visiting a denist will have a tooth extracted is 0.06, the probability that he will have a cavity filled is 0.2, and the probability that he will have a tooth extracted or a cavity filled is 0.23.What is the probability that he will have a tooth extracted as well as a cavity filled? Solution: Let A denote the event that a patient visiting a denist will have a tooth extracted and B denote the event that a patient will have a cavity filled Given : $P(A)=0.0...
Read More →Silicon doped with electron rich
Question: Silicon doped with electron rich impurity forms ________. (i) p-type semiconductor (ii) n-type semiconductor (iii) intrinsic semiconductor (iv) insulator Solution: Option (ii)n-type semiconductor is the answer....
Read More →Which kind of defects are introduced
Question: Which kind of defects are introduced by doping? (i) Dislocation defect (ii) Schottky defect (iii) Frenkel defects (iv) Electronic defects Solution: Option (iv)Electronic defects is the answer....
Read More →What is the coordination number in a square
Question: What is the coordination number in a square close-packed structure in two dimensions? (i) 2 (ii) 3 (iii) 4 (iv) 6 Solution: Option (iii)4is the answer....
Read More →Evaluate the following integrals:
Question: Evaluate the following integrals: $\int \frac{1}{1-\sin x+\cos x} d x$ Solution: Given $I=\int \frac{1}{1-\sin x+\cos x} d x$ We know that $\sin \mathrm{x}=\frac{2 \tan \frac{x}{2}}{1+\tan \frac{x}{2}}$ and $\cos \mathrm{x}=\frac{1-\tan ^{2} \frac{x}{2}}{1+\tan ^{2} \frac{x}{2}}$ $\Rightarrow \int \frac{1}{1-\sin x+\cos x} d x=\int \frac{1}{1-\frac{2 \tan \frac{x}{2}}{1+\tan ^{2} \frac{x}{2}}+\frac{1-\tan \frac{2}{2}}{1+\tan ^{2} \frac{2}{2}}} d x$ $=\int \frac{1+\tan ^{2} \frac{x}{2}}...
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