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questions
List of practice Questions
If Young?s double slit experiment is done with white light, which of the following statements will be true ?
WBJEE - 2018
WBJEE
Physics
Wave optics
Let
$\vec{\alpha } = \hat{i} + \hat{j} + \hat{k} , \vec{\beta} = \hat{i} - \hat{j} - \hat{k}$
and
$\vec{\gamma} = - \hat{i} + \hat{j} - \hat{k}$
be three vectors. A vector
$\vec{\delta} $
, in the plane of
$\vec{\alpha}$
and
$\vec{\beta}$
, whose projection on
$\vec{\gamma}$
is
$\frac{1}{\sqrt{3}}$
, is given by
WBJEE - 2018
WBJEE
Mathematics
Product of Two Vectors
On the set
$R$
of real numbers, the relation
$\rho$
is defined by
$x \rho y, (x, y) \in R$
WBJEE - 2018
WBJEE
Mathematics
types of relations
If $\int \, f(x) \, \sin \, x \, \cos \, x \, dx = \frac{1}{2(b^2 - a^2)} \log f(x) + c$, where c is the constant of integration , then f(x) =
WBJEE - 2018
WBJEE
Mathematics
Definite Integral
The approximate value of $\sin \, 31^{\circ}$ is
WBJEE - 2018
WBJEE
Mathematics
measurement of angles
The value of $\displaystyle\lim_{n \to \infty} \frac{1}{n} \left\{ \sec^2 \frac{\pi}{4 n} + \sec^2 \frac{2 \pi }{4n} + ..... \sec^2 \frac{n \pi}{4n} \right\}$ is
WBJEE - 2018
WBJEE
Mathematics
limits of trigonometric functions
Which is least thermally stable?
WBJEE - 2018
WBJEE
Chemistry
GROUP 1 ELEMENTS
The ease of hydrolysis in the compounds $CH _{3} COCl ( I ), CH _{3}- CO - O - COCH _{3}( II )$ $CH _{3} COOC _{2} H _{5}( III )$ and $CH _{3} CONH _{2}( IV )$ is of the order
WBJEE - 2018
WBJEE
Chemistry
Chemical Reactions
The main reason the $SiCl_4$ is easily hydrolysed as compared to $CCl_4$ is that
WBJEE - 2018
WBJEE
Chemistry
GROUP 14 ELEMENTS
In the extraction of Cu, the metal is formed in the bessemer converter due to the reaction:
VITEEE - 2018
VITEEE
Chemistry
Concentration of ores
Ionisation energy of
$He^+$
is
$19.6 \times 10^{-18}\, J$
atom
$^{-1}$
. The energy of the first stationary state
$(n= 1)$
of
$Li^{2+}$
is
VITEEE - 2018
VITEEE
Chemistry
Bohr’s Model for Hydrogen Atom
In a compound, atoms of element Y form ccp lattice and those of element X occupy $2/3^{rd}$ of tetrahedral voids. The formula of the compound will be
VITEEE - 2018
VITEEE
Chemistry
Unit Cells
In case of nitrogen, $NCl_3$ is possible but not $NCl_5$ while in case of phosphorus, $PCl_3$ as well as $PCl_5$ are possible. It is due to
VITEEE - 2018
VITEEE
Chemistry
Group 15 Elements
In Williamson synthesis if tertiary alkyl halide is used than
VITEEE - 2018
VITEEE
Chemistry
Ethers
A football is inflated by pumping air in it. When it acquires spherical shape its radius increases at the rate of 0.02 cm/s. The rate of increase of its volume when the radius is 10 cm is ___________
$\pi$
cm/s
VITEEE - 2018
VITEEE
Mathematics
Rate of Change of Quantities
A large number of liquid drops each of radius r coalesce to from a single drop of radius R. The energy released in the process is converted into kinetic energy of the big drop so formed. The speed of the big drop is (given, surface tension of liquid T, density
$\rho$
)
VITEEE - 2018
VITEEE
Physics
Surface Tension
For the LPP; maximise
$z =x + 4y$
subject to the constraints
$x + 2y \leq 2, x +2 y \ge 8, x, y \ge 0$
VITEEE - 2018
VITEEE
Mathematics
lpp graphical method
An element occuring in the bcc structure has
$12.08 \times 10^{23}$
unit cells. The total number of atoms of the element in these cells will be
VITEEE - 2018
VITEEE
Chemistry
Unit Cells
A metal disc of radius
$100 \,cm$
is rotated at a constant angular speed of
$60$
rad/s in a plane at right angles to an external field of magnetic induction
$0.05\, Wb/m^2$
. The emf induced between the centre and a point on the rim will be
VITEEE - 2018
VITEEE
Physics
Electromagnetic induction
One mole of a mono-atomic ideal gas undergoes a quasi-static process, which is depicted by a straight line joining points
$(V_0, T_0)$
and
$(2V_0, 3T_0)$
in a
$V-T$
diagram. What is the value of the heat capacity of the gas at the point
$(V_0, T_0)$
?
WBJEE - 2018
WBJEE
Physics
specific heat capacity
Which one is a synthetic Auxin:
UPSEE - 2018
UPSEE
Biology
Hormones
Match the items given in Column I with those in Column II and select the correct option given below:
NEET (UG) - 2018
NEET (UG)
Biology
excretory products and their elimination
A tuning fork is used to produce resonance in glass tube. The length of the air column in the tube can be adjusted by a variable piston, A room temperature of
$27^{\circ} C$
two successive resonances are produced at
$20\, cm$
and
$73\, cm$
column length. If the frequency of the tuning for is
$320\, Hz$
, the velocity of sound in air at
$27^{\circ} C$
NEET (UG) - 2018
NEET (UG)
Physics
Waves
Which part of poppy plant is used to obtain the drug "Smack" ?
NEET (UG) - 2018
NEET (UG)
Biology
Human health and disease
Which of the following is not an autoimmune disease ?
NEET (UG) - 2018
NEET (UG)
Biology
Human health and disease
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