1.When a bicycle is in motion, the force of friction exerted by the ground on the two wheels is such that it acts
(a) In the backward direction on the front wheel and in the forward direction on the rear wheel.
(b) In the forward direction on the front wheel and in the backward direction on the rear wheel.
(c) In the backward direction on both the front and rear wheels.
(d) In the backward direction on both the front and rear wheels.
Ans. (d)
2. A certain radioactive element A, has a half life = t seconds.In (t/2) seconds the fraction of the initial quantity of the element so far decayed is nearly
(a) 29%
(b) 15%
(c) 10%
(d) 45%
Ans. (a)
3. Which of the following plots would be a straight line ?
(a) Logarithm of decay rate against logarithm of time
(b) Logarithm of decay rate against logarithm of number of decaying nuclei
(c) Decay rate against time
(d) Number of decaying nuclei against time
Ans. (b)
4. A radioactive element x has an atomic number of 100.It decays directly into an element y which decays directly into element z. In both processes a charged particle is emitted. Which of the following statements would be true?
(a) y has an atomic number of 102
(b) y has an atomic number of 101
(c) z has an atomic number of 100
(d) z has an atomic number of 101
Ans. (b)
5. If the sum of the roots of the equation ax2 + bx + c=0 is equal to the sum of the squares of their reciprocals then a/c, b/a, c/b are in
(a) AP
(b) GP
(c) HP
(d) None of these
Ans. (c)
6. A man speaks the truth 3 out of 4 times. He throws a die and reports it to be a 6. What is the probability of it being a 6?
(a) 3/8
(b) 5/8
(c) 3/4
(d) None of the above
Ans. (a)
7. If cos2A + cos2B + cos2C = 1 then ABC is a
(a) Right angle triangle
(b) Equilateral triangle
(c) All the angles are acute
(d) None of these
Ans. (a)
8. Image of point (3,8) in the line x + 3y = 7 is
(a) (-1,-4)
(b) (-1,4)
(c) (2,-4)
(d) (-2,-4)
Ans. (a)
9. The mass number of a nucleus is
(a) Always less than its atomic number
(b) Always more than its atomic number
(c) Sometimes more than and sometimes equal to its atomic number
(d) None of the above
Ans. (c)
10. The maximum KE of the photoelectron emitted from a surface is dependent on
(a) The intensity of incident radiation
(b) The potential of the collector electrode
(c) The frequency of incident radiation
(d) The angle of incidence of radiation of the surface
Ans. (c)
11. Which of the following is not an essential condition for interference
(a) The two interfering waves must be propagated in almost the same direction or the two interfering waves must intersect at a very small angle
(b) The waves must have the same time period and wavelength
(c) Amplitude of the two waves should be the same
(d) The interfering beams of light must originate from the same source
Ans. (c)
12. When X-Ray photons collide with electrons
(a) They slow down
(b) Their mass increases
(c) Their wave length increases
(d) Their energy decreases
Ans. (c)
13. An electron emits energy
(a) Because its in orbit
(b) When it jumps from one energy level to another
(c) Electrons are attracted towards the nucleus
(d) The electrostatic force is insufficient to hold the electrons in orbits
Ans. (b)
14. How many bonds are present in CO2 molecule?
(a) 1
(b) 2
(c) 0
(d) 4
Ans. (d)
15. In a balanced chemical equation
(a) Atoms are conserved
(b) Molecules are conserved
(c) Moles are conserved
(d) Reactant and product molecules are preserved
Ans. (a)
16. How many grams of NaOH will react with 0.2 equivalent of HCl?
(a) 0.59
(b) 0.285
(c) 1.18
(d) none of these
Ans. (a)
17. Which of the following is least acidic
(a) Ortho-cresol
(b) Para-cresol
(c) Phenol
(d) Meta-cresol
Ans. (b)
18. In Reimer-Tiemann's reaction, the reaction intermediate is
(a) Carbene
(b) Dichloro carbene
(c) Carbonion
(d) Carbonium ion
Ans. (b)
19. Which of the following is most acidic?
(a) C2H5OH
(b) CH3CHOHCH3
(c) Ethanol
(d) CH3OH
Ans. (b)
20.A catalyst
(a)always slows down the reaction
(b)always starts a rection that would not have ocurred at all otherwise
(c)causes changes in the rate of the reaction
(d)changes the quantities of the products formed
Ans. (c)
