List of practice Questions

In a potentiometer experiment, the balancing length of a cell is $560\, cm$. When an external resistance of $10 \, \Omega$ is connected in parallel to the cell, the balancing length changes by $60 \,cm$.The internal resistance of a cell is
Two sources of equal emf are connected to a resistance $R$. The internal resistance of these sources are $r_1$ and $r_2 (r_1 > r_2 )$. If the potential difference across the source having internal resistance $r_2$ is zero, then
A current of $2\,A$ is flowing in the sides of an equilateral triangle of side $9\, cm$. The magnetic field at the centroid of the triangle is
A horizontal rod of mass $0.01\,kg$ and length$ 10\, cm $ is placed on a frictionless plane inclined at an angle $60^{\circ}$ with the horizontal and with the length of rod parallel to the edge of the inclined plane. A uniform magnetic field is applied ?Vertically downwards. If the current through the rod is $1.73\, A$, then the value of magnetic field induction $B$ for which the rod remains stationary on the inclined plane is
Statements: I. Some vegetables are fruits.
II. No fruit is black. Conclusions: I. Some fruits are vegetables.
II. No vegetable is black.
Consider the water gas equilibrium reaction, $C ( s )+ H _{2} O ( g ) \rightleftharpoons CO ( g )+ H _{2}( g )$ Which of the following statements is true at equilibrium?
Point out incorrect stability order
The molarity of $NO_3^-$ in the solution after $2L$ of $3M \, AgNO_3$ is mixed with $3L$ of $1M \, BaCl_2$ is
The chemical composition of slag formed during the smelting process in the extraction of copper is
Caffeine has a molecular weight of $194\, u$. If it contains $28.9\%$ by mass of nitrogen, number of atom of nitrogen in one molecule of caffeine is
In benzene, the triple bond consists of
$X Cl _{2}( excess )+Y Cl _{2} X Cl _{4}+Y \downarrow$ $Y O {->[{\Delta}][{>400^{\circ} C }]} \frac{1}{2} O _{2}+Y$ Ore of Y would be ,
Consider the following changes $M(s) \longrightarrow M(g)$ $M(g) \longrightarrow M^{2+}(g)+2 e^{-}\ldots$(1) $M(g) \longrightarrow M^{+}(g)+e^{-}\ldots$(2) $M^{+}(g) \longrightarrow M^{2+}(g)+e^{-} \ldots$ (3) $M(g) \longrightarrow M^{2+}(g)+2 e^{-}\ldots$(4) The second ionisation energy of $M$ could be determined from the energy values associated with
If the ionisation energy and electron affinity of an element are $275$ and $86 \,kcal\, mol^{-1}$ respectively, then the electronegativity of the element on the Mulliken scale is
With excess of water, both $P_{2}O_{5}$ and $PCl_{5}$ give
Which one of the following is a case of negative adsorption?
A certain metal when irradiated by light $(r = 3.2 \times 10^{16} Hz)$ emits photoelectrons with twice kinetic energy as did photoelectrons when the same metal is irradiated by light $(r =2.0 \times 10^{16} Hz)$. The $v_0$ of metal is
An alloy of copper, silver and gold is found to have copper atom constituting the ccp lattice. If silver atom occupy the edge centres and gold atom is present at body centred, the alloy has a formula
An n-type semiconductor is
The refractive index for a prism is given as $\mu = \cot \frac{A}{2}$. Then, angle of minimum deviation in terms of angle of prism is
A galvanometer with a scale divided into $100$ equal divisions has a current sensitivity of $10$ divisions per milliampere and a voltage sensitivity of $2$ divisions per millivolt. The galvanometer resistance will be
An electron of mass $9.0 \times 10^{-31} kg$ under the action of a magnetic field moves in a circle of radius $2\, cm$ at a speed of $3 \times 10^6 \, m/s$ . If a proton of mass $1.8 \times 10^{27} \, kg$ was to move in a circle of same radius in the same magnetic field, then its speed will become
A $30\,V-90\,W$ lamp is operated on a $120\,V$ DC line. A resistor is connected in series with the lamp in order to glow it properly. The value of resistance is
Two points masses, $m$ each carrying charges $-q$ and $+q$ are attached to the ends of a mass less rigid non-conducting wire of length $'L'$. When this arrangement is placed in a uniform electric field, then it deflects through an angle $i$. The minimum time needed by rod to align itself along the field is
Two polaroids are kept crossed to each other. If one of them is rotated an angle $60^{\circ}$, the percentage of incident light now transmitted through the system is