Q1.The wavelength of X-rays is of the order of
(a) 1 mm
(b) 1 cm
(c) 1 micron
(d) 1 angstromQ2. How many sixty watt (60 W) bulbs may be safely used in a 240-V supply with 4-ampere fuse?
(d) 16Q3. Potential at a point due to a point charge is V. The charge is doubled and also the distance of the point from the charge is doubled. The new potential is
(b) 4 V
(d) 2 VQ4. The polarity of an unmarked horse shoe magnet can be determined by using
(a) a charged glass rod
(b) a magnetic compass
(c) an electroscope
(d) another unmarked bar magnetQ5. 5. Nuclear fusion reactions require very temperatures so as to overcome:
(a) van der Waals’ forces
(b) Nuclear forces
(c) Gravitational forces
(d) Coulomb forces Q6. If an a-particle is projected normally through a uniform magnetic field, then the path of the a-particle inside the field will be
(d) a straight lineQ7. Why is helium preferred over hydrogen for use in airships?
(a) Helium has a low density
(b) Helium has a high density
(c) Helium is chemically less reactive
(d) Helium is chemically more reactive. Q8. An element A has valencies equal to 3 and 5. It combines with another element B having valency equal to
2. What are formulae of the compounds thus formed?
(a) A5B3 and A2B5
(b) A3B2 and A5B2
(c) A2B3 and A2B5
(d) A2B3 and A3B5 Q9. The deficiency of which one of the following leads to dental caries?
(d) Zinc Q10. Which one among the following most correctly determines the atomic number of an element?
(a) Number of protons
(b) Number of protons and electrons
(c) Number of ions
(d) Number of nucleonsQ11. The following questions consist of two statements, one labelled as the Assertion (A) and the other as ‘Reason (R), You are to examine these two statements carefully and select the answers to these items using the codes given below:
Assertion (A): Atomic weights of most of the elements are not whole numbers.
Reason (R): Atoms of most of the elements contain mixture of isotopes having different atomic weights.
(a) Both A and R are individually true and R is the correct explanation of A
(b) Both A and R are individually true but R is NOT the correct explanation of A
(c) A is true but R is false
(d) A is false but R is trueQ12. Which one among the following statements is not correct about graphite?
(a) It is the most stable allotrope of carbon
(b) It is an electrically conducting material
(c) Crystalline spherical beads of graphite have very good lubricating property under dry conditions
(d) It is the higher grade of coal
1. (d)2. (d)3. (c)4. (b)5. (d)6. (a)7. (c)8. (c)9. 10. (a)11. (a)12. (b)