List of practice Questions

Chemistry of lanthanides ($ \text{Ln} $) is dominated by +3 oxidation state. Which of the following is incorrect?
Which of the following molecules is not linear?
A capacitor and a resistor are connected in series to an ac source of variable frequency. When the frequency of the ac source becomes $ \frac{1}{3} $rd of its initial value, the current in the circuit decreases by 50%. The power factor of the circuit at the initial frequency is
If the electric field of an electromagnetic wave is increased by 100%, then the energy density of the wave increases by
A radioactive element A with half life 3 hours decays to a stable element B. After a time $ t $, the ratio of A and B atoms is 1:16 then the time $ t $ in hours is
The force between two spheres with charges +7 $ \mu C $ and -5 $ \mu C $ is F. If each sphere is given an additional charge of +2 $ \mu C $, the new force of attraction will be
A liquid of density $ 3000 \, \text{kg/m}^3 $ and coefficient of viscosity $ 0.1 \, \text{Pas} $ flows through a pipe with diameter $ 0.05 \, \text{m} $ with a velocity of $ 0.2 \, \text{m/s} $. The Reynolds number of the fluid is
A hot fluid cools from 200°C to 100°C in 5 minutes. Then the time taken by it to cool from 100°C to 50°C is nearly (Room temperature = 30°C)
At atmospheric pressure, 1 g of water has a volume of 1671 cm³ in vapor phase. The change in internal energy when 1 g of water changes from liquid to vapor phase at atmospheric pressure is
Two cars of different masses have same kinetic energy, then
Two boys A and B with masses 30 kg and 20 kg respectively are at the two extremes of a boat of mass 50 kg and length 5 m resting still on water. Boys A and B move towards each other and meet at the midpoint of the boat. During the process, the distance moved by the boat and boys is (Neglect friction between water and boat)
Two objects separated by a distance r gravitationally attract each other with force F. If the distance between them is tripled, the force of attraction between them is
From an elevated point 'A', a stone is projected vertically upwards. The velocity of the stone when it reaches a distance 'h' below 'A' is double its velocity when it was at a height 'h' above 'A'. The greatest height attained by the stone above 'A' is
For two vectors $ \mathbf{A} $ and $ \mathbf{B} $, if $ \mathbf{A} + \mathbf{B} = |\mathbf{A} - \mathbf{B}| $, then
A body of mass 90 g is connected to a string of 100 cm length and whirled in a horizontal circle. If the string can withstand a tension of 2.25 N, then permissible maximum velocity of the body is

A disaccharide X cannot be oxidised by bromine water. The acid hydrolysis of X leads to a laevorotatory solution. The disaccharide X is

An ideal gas is in thermodynamic equilibrium. The number of degrees of freedom of a molecule of the gas is 𝑛. The internal energy of one mole of the gas is 𝑈𝑛 and the speed of sound in the gas is v𝑛. At a fixed temperature and pressure, which of the following is the correct option?
In list - I some conversions are shown and in the list- II emitted particles are shown. Match the column
 List-I List- II
(P) \(_{92}^{238}\textrm{U}\) → \(_{91}^{234}\textrm{Pa}\)(1)one α particle and one β+ particle
(Q) \(_{82}^{214}\textrm{Pb}\) → \(_{82}^{210}\textrm{Pb}\)(2) Three β- particle and 1 α particle
(R) \(_{81}^{210}\textrm{Tl}\) → \(_{82}^{206}\textrm{Pb}\)(3) Two β- particle and 1 α particle
(S) \(_{81}^{228}\textrm{Pa}\)→ \(_{88}^{224}\textrm{Ra}\)(4) one α particle and one β- particle
  (5) one α particle and two β+ particle
first reflection

Taking the first reflection of M1. If the final image coincides with s, then find n.
The degree of freedom of an ideal gas is n. The internal energy of 1 mole of the gas is Un and the speed of sound n the gas is Vn. At a fixed temperature and pressure, which of the following is correct?
A ball is released on a smooth plane as shown. It strikes with the ground, the coefficient of restitution is \(\frac{1}{\sqrt{3}}\) Choose the correct options
A ball is released on a smooth plane
Find the α, β, γ in the Y = \(C^\alpha h^\beta G^\gamma,\,\,\) 
\(\gamma\) = Young's Modulus
 \(c\) = speed of Light
 \(h\) = Plank's Constant
 \(G\) = gravitational Constant

If \(P(B) = \frac{3}{5}\), \(P(A/B) = \frac{1}{2}\), and \(P(A \cup B) = \frac{4}{5}\), then \(P(A \cup B)' + P(A')\) is : 

\(\int x^x(1 + \log x) \, dx\), \(\text{ is equal to:}\)

One volt induced emf is produced in the secondary coil when the current through the primary coil is changed from 3 A to 1 A in 100 milliseconds. The mutual inductance of the two coils is: