List of practice Questions

The length of an elastic string is a metre, when the longitudinal tension is 4 N and the length is $b$ m, when the tension is 5 N. When the longitudinal tension is 9 N, the length of the string (in metre) is
On a particular day, the maximum frequency reflected from the ionosphere is 9 MHz. On another day, it was found to increase by 1 MHz. What is the ratio of the maximum electron densities of the ionosphere on the two days?
A bus travelling the first one-third distance at a speed of ${10 \, km \, h^{-1}}$, the next one-third at ${20 \, km \, h^{-1}}$ and last one third at ${60 \, km \, h^{-1}}$. The average speed of bus is
A man standing on the road has to hold his umbrella at 30 degrees from the vertical direction to keep the rain away. He thrown away the umbrella and starts running at ${10\, km \, h^{-1}}$, he finds that the rain drops are hitting him vertically. The speed of the rain drops w.r.t. the road is
A projectile is fired vertically upwards from the surface of the Earth with a velocity $k\upsilon _e$ , where $\upsilon_e$ is the escape velocity and $k < 1$ . If $R$ is the radius of the Earth, the maximum height to which it will rise measured from the centre of the Earth will be
Structure of a mixed oxide is cubic close packed $(ccp)$. The cubic unit cell of mixed oxide is composed of oxide ions. One fourth of the tetrahedral voids are occupied by divalent metal A. The octahedral voids are occupied by a monovalent metal B. The formula of the oxide is
The coagulation of 200 mL of a positive colloid took place when 0.73 g HCl was added to it without changing the volume much. The flocculation value of HCl for the colloid is
The component of a vector $\vec{r}$ along $x$-axis will have maximum value if
The composition of ?copper matte? is,
The complex formed when $Al_2O_3$ is leached from Bauxite using concentrated NaOH solution is,
Sulphur sol contains
Reactions in zeolite catalyst depend on,
Main axis of a diatomic molecule is $Z$, molecular orbital $p_x $ and $ p_y$ overlaps to form, which of the following orbitals?
If the straight lines $2x + 3y - 3 = 0$ and $x + ky + 7 = 0$ are perpendicular, then the value of $k$ is
If $a = 3, b = 4, c = 5$ each one of $a ,b$ & $c$ is perpendicular to the sum of the remaining then $| a + b + c | $ is equal to
$HCl$ gas is covalent and $NaCl$ is an ionic compound. This is because
A conducting wire carrying current is arranged as shown. The magnetic field at $'O'$
Which of the following chromosomes are responsible for most of the sexlinked traits?
The carbocation formed in $ S_N1 $ reaction of alkyl halide in the slow step is:
The position vector $\vec{r}$ of a particle of mass $m$ is given by the following equation $\vec{r}(t)=\alpha t^{3} \hat{i}+\beta t^{2} \hat{j}$ where $\alpha=\frac{10}{3} \,ms ^{-3}, \beta=5\, ms ^{-2}$ and $m =0.1 \,kg$. At $t =1\, s$, which of the following statement (s) is (are) true about the particle?
For the reaction $2SO_2 + O_2$ (excess) $\rightarrow\, 2SO_3$ the order of reaction with respect to $O_2$ is
The value of ($\Delta H - \Delta E$) for the reaction $C_6H_6(1) + 7\frac{1}{2} O_2(g) \rightarrow 6CO_2(g) + 3H_2O(I)$ at 270C is (R = 2 cal K-1 mol-1)
Magnitude of binding energy of satellite is $E$ and kinetic energy is $K$ .The ratio $E/K$ is
The frequencies of $X-$ rays, Gamma rays and visible light waves rays are $a, b$ and $c$ respectively, then
An electron is at ground state of the $H$ atom. Minimum energy required to excite the $H$ atom into second excited state is