Wipro Placement Papers-2

1. When X-Ray photons collide with electrons

They slow down

Their mass increases

Their wave length increases

Their energy decreases

2. 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?

Y has an atomic number of 102

Y has an atomic number of 101

Z has an atomic number of 100

Z has an atomic number of 101

3. 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

29%

15%

10%

45%

4. Which of the following is most acidic?

C2H5OH

CH3CHOHCH3

Ethanol

CH3OH

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

AP

GP

HP

None of these

6. If cos2A + cos2B + cos2C = 1 then ABC is a

Right angle triangle

Equilateral triangle

All the angles are acute

None of these

7. The maximum KE of the photoelectron emitted from a surface is dependent on

The intensity of incident radiation

The potential of the collector electrode

The frequency of incident radiation

The angle of incidence of radiation of the surface

8. Which of the following plots would be a straight line ?

Logarithm of decay rate against logarithm of time

Logarithm of decay rate against logarithm of number of decaying nuclei

Decay rate against time

Number of decaying nuclei against time

9. A catalyst

Always slows down the reaction

Always starts a reaction that would not have ocurred at all otherwise

Causes changes in the rate of the reaction

Changes the quantities of the products formed

10. 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?

3/8

5/8

3/4

None of these

11. Which of the following is least acidic

Ortho-cresol

Para-cresol

Phenol

Meta-cresol

12. An electron emits energy

Because its in orbit

When it jumps from one energy level to another

Electrons are attracted towards the nucleus

The electrostatic force is insufficient to hold the electrons in orbits

13. In a balanced chemical equation

Atoms are conserved

Molecules are conserved

Moles are conserved

Reactant and product molecules are preserved

14. The mass number of a nucleus is

Always less than its atomic number

Always more than its atomic number

Sometimes more than and sometimes equal to its atomic number

None of the above

15. How many bonds are present in CO2 molecule?

1

2

0

4

16. Image of point (3,8) in the line x + 3y = 7 is

(-1,-4)

(-1,4)

(2,-4)

(-2,-4)

17. Which of the following is not an essential condition for interference

The waves must have the same time period and wavelength

Amplitude of the two waves should be the same

The interfering beams of light must originate from the same source

18. Find the Antonyms of the following words1.When a bicycle is in motion,the force of friction exerted by the ground on the two wheels is such that it acts

In the backward direction on the front wheel and in the forward direction on the rear wheel.

In the forward direction on the front wheel and in the backward direction on the rear wheel.

In the backward direction on both the front and rear wheels.