List of practice Questions

An electron in the hydrogen atom jumps from excited state n to the ground state. The wavelength so emitted illuminates a photosensitive material having work function $2.75 \,eV$. If the stopping potential of the photoelectron is $10 \,V$ , then the value of $n$ is
Fusion reaction takes place at high temperature because
A body is moving with velocity $30\, ms$ towards east After 10 s its velocity becomes $40 \,ms$ towards north. The average acceleration of the body is
According to the Bohr Theory, which of the following transitions in the hydrogen atom will give rise to the least energetic photon?
A solid compound $XY$ has $NaCl$ structure. If the radius of the cation is $100\, pm$, the radius of the anion $(Y^-)$ will be -
Suppose $ P(2,\,y,\,z) $ lies on the line through $ A(3,-1,4) $ and $ B(-4,2,1) $ . Then, the value of z is equal to
Consider the following four conditions $(a-d)$ and select the correct pair of them as adaptation to environment in desert lizards. The conditions: 1. Burrowing in soil to escape high temperature. 2. Losing heat rapidly from the body during high temperature. 3. Bask in sun when temperature is low. 4. Insulating body due to thick fatty dermis.
In $n$ is an odd positive integer and $(1+x +x^2 +x^3)^n =\displaystyle\sum_{r=0}^{3n} a_rx^r$ then $a_0 -a_1+a_2-a_3 +\dots -a_{3n}$ is equal to
Angles of elevation of the top of a tower from three points (collinear) $A, B$ and $ C$ on a road leading to the foot of the tower are $30^\circ$, $45^\circ$ and $60^\circ$ respectively. The ratio of $AB$ to $BC$ is
The derivative of $tan ^{-1}[\frac{Sin x}{1+ Cos x}]$ with respect to $tan^{-1}[\frac{Cos x}{1+Sin x}]$ is
The value of $\left| \frac{1+ i \sqrt{3}}{\left( 1 + \frac{1}{i+1}\right)^2} \right|$ is
The sum of the first n terms $ \frac {1^2}{1} +\frac {1^2+2^2}{1+2}+ \frac {1^2 +2^2+3^2}{1+2+3}+$ $\dots$ is
The complex, $[Pt(Py)(NH_3)Br\,Cl]$ will have how many geometrical isomers?
A radioactive nucleus of mass $M$ emits a photon of frequency $\upsilon$ and the nucleus recoils. The recoil energy will be
Which one of the following is present as an active ingredient in bleaching powder for bleaching action?
Agarose extracted from sea weeds finds used in
Three of the following pairs of the human skeletal parts are correctly matched with their respective inclusive skeletal category and one pair is not matched. Identify the non-matching pair. .
Pair of skeletal parts Category
(a)$\,\,$ Sternum and ribs$\,\,$ Axial skeleton
(b)$\,\,$ Clavicle and glenoid cavity$\,\,$ Pelvic girdle
(c)$\,\,$ Flumerus and ulna$\,\,$ Appendicular skeleton
(d)$\,\,$ Malleus and stapes$\,\,$ Ear ossicles
Which one of the following is the most wide accepted method of contraception in India at present?
A TV tower has a height 150 m. What is the total population covered by the TV tower, if the population density around the TV tower is $10^3\, km^{-2}?$ Radius of the earth is $6.4\times10^{6}m$
An electric dipole is placed in an uniform electric field with the dipole axis making an angle $ \theta $ with the direction of the electric field. The orientation of the dipole for stable equilibrium is
A radioactive nucleus of mass number $A$, initially at rest, emits an $ \alpha$ - particle with a speed $v$. The recoil speed of the daughter nucleus will be
A constant torque of $ 3.14\,Nm $ is exerted on a pivoted wheel. If the angular acceleration of the wheel is $ 4\pi \,rad/s^{2}, $ then the moment of Inertia of the wheel is
The rms velocity of hydrogen is $\sqrt {7}$ times the rms velocity of nitrogen. If $T$ is the temperature of the gas, which of the following is true?
A particle of charge $e$ and mass $m$ moves with a velocity $v$ in a magnetic field $B$ applied perpendicular to the motion of the particle. The radius $r$ of its path in the field is
If $\alpha , \beta ,\gamma$ are the roots of $x^3-2x+1=0$, then the value of $(\sum \frac {1} {\alpha +\beta -\gamma}$) is