IIT-JEE Practise paper-13 [Test]

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Muggu

IIT-JEE Practise paper-13

A test by Muggu.

Test Questions

Question

The ratio of the wave lengths of last lines of Balmer and Lyman series is-

Answers

Correct	Answer Text
	27:5
	9:4
	3:1
	4:1

Question

Using arbitrary energy units we can calculate that 864 arbitary units (a.u.) are required to transfer an electron in hydrogen atom from the most stable Bohr’s orbit to the largest distance from the nucleus;

$n=\infty \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad$ E = 0 Arbitary units
n = 4
n = 3
n = 2
$n = 1 \quad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad$ E = –864 Arbitary units
The energy required to transfer the electron from third Bohr orbit to the orbit $n =\infty$ will be;

Answers

Correct	Answer Text
	384 Arbitary units
	288 Arbitary units
	96 Arbitary units
	192 Arbitary units

Question

The decomposition of nitrosyl chloride is described by the equation:

$2NOCl(g) \leftrightharpoons 2NO(g) + Cl_2(g)$

A round –bottom flask initially contains pure NOCl gas at 400 K and a pressure of 2.75 atm. When the equilibrium is reached the total pressure is equal to 3.58 atm. What is the value of K_p ?

Answers

Correct	Answer Text
	0.36 atm
	1.93 atm
	0.16 atm
	1.26 atm

Question

During the particular reaction 10% of the reactant decomposes in one hour 20% in two hours 30% in three hours and so on. The unit of the rate constant is

Answers

Correct	Answer Text
	$Hour^{-1}$
	$mol L^{-1} \quad hour^{-1}$
	$L\quad mol^{-1} \quad hour^{-1}$
	$mol\quad hour^{-1}$

Question

Answer the following 5 questions on the basis of the given below paragraph.

Natural uranium contains two isotopes: $^{238}U$ and the much rarer $^{235}U$ . The latter is the isotope responsible of the vast release of energy during nuclear fission. They two major uses of $^{235}U$ are in nuclear reactors and in atomic bombs. Both of these processes rely on self-sustaining fission reactions.

The radioactive disintegration of $^{235}U$ involves, as a first step, the incorporation of a slow moving neutron into its nucleus. All of the neutrons released during nuclear fission are capable of splitting another $^{235}U$ nucleus. Each reaction produces three neutrons and provided that the chain can build up rapidly enough, there is an enormous release of energy and this is the basis of the action of the atomic bomb. This will only occur if the $^{235}U$ sample present is larger than a certain mass known as the critical size. In the atomic bomb two pieces of pure $^{235}U$ or $^{239}Pu$ each below the critical size are brought together and the two pieces form one piece larger than the critical size and this leads to the explosion observed.

In the nuclear reactor, the atomic pile consists of rods of uranium inserted into channels surrounded by blocks of graphite. The temperature of the pile can be controlled by the use of movable boron or cadmium rods. The heat generated during the fission process is removed by a stream of carbon dioxide. The hot gas is then used to produce steam which drives a turbine and so produces electrical energy.
Why must the uranium rods be stored well apart before use in the reactor?

Answers

Correct	Answer Text
	Because an explosion could occur.
	Because they are then easier to transport
	Because a fusion reaction would begin while in storage.
	Because conversion of $^{235}U$ to non-fissionable $^{238}U$ would occur.

Question

In an atomic bomb, the chain reaction depends on;

Answers

Correct	Answer Text
	at least four neutrons produced from a $^{235}U$ nucleus splitting other nucleus.
	none of the above
	all three neutrons produced from a $^{235}U$ nucleus splitting other $^{235}U$ .
	at least two neutrons produced form a $^{235}U$ nucleus splitting another $^{235}U$ nucleus.

Question

Given the following reactions, identify X.

$^1_0n+^{238}_{92}U \rightarrow U + X$

$^{239}_{92}U \rightarrow ^{239}_{93}Np + ^0_{-1}e$

$^{239}_{93}Np \rightarrow ^{239}_{94}Pu + ^0_{-1}e$

Answers

Correct	Answer Text
	electron
	positron
	proton
	neutron

Question

The Dounreay Nuclear Power Station has been in operation for quite some time. Over the last six years, they have turned out a total of two megawatt- years of energy. Assuming that operation were continuous over the six year period at a constant rate, what was its power in watts?

Answers

Correct	Answer Text

Question

Nuclear reactors are usually surrounded by lead and concrete. Which of the following is this safety precaution particularly for?

Answers

Correct	Answer Text
	proton
	$\beta$ -particle
	$\alpha$ -particle
	$\gamma$ -rays

Question

In the following question, a statement of Assertion (A) is given and a corresponding statement of Reason (R) is given just below it. Of the statement, mark the correct aanswer as;

Assertion: In the Haber process,
$N_2+3H_2 \leftrightharpoons 2NH_3$ pressure is about 200 atm in presence of catalyst and temperature is kept 500^0C even the reaction is exothermic.
Reason: Energy needed for this reaction is easily obtained at this temperature.

Answers

Correct	Answer Text
	both A and R are true but R is not the correct explanation of A
	A is true but R is false
	both A and R are true and R is the correct explanation of A
	A is false but R is true