List of practice Questions

About $6\%$ of the power of a $100\, W$ light bulb is converted to visible radiation. The average intensity of visible radiation at a distance of $8\, m$ is (Assume that the radiation is emitted isotropically and neglect reflection.
Absence of circulatory system in Hydra is compensated by
A120 V, 60Hz a.c. power is connected $800\Omega$ non-inductive resistance and unknown capcitance in series. The voltage drop across the resistance is found to be 102V, then voltage drop across eapacitor is
ABC is a triangle and AD is the median. If the coordinates of A are ( 4, 7, - 8)and the coordinates of centroid of the triangle ABC are (1, 1, 1), what are the coordinates of D?
ABCD is a convex quadrilateral. 3, 4, 5 and 6 points are marked on the sides AB, BC, CD and DA respectively . The number of triangles with vertices on different sides is
A wire of length $L$, radius $r$ when stretched with a force $F$ changes in length by $l$. What will be the change in the length of a wire of same material having length $2L$, radius $2r$ and stretched by a force $2F$ ?
A wire of resistance R is elongated n-fold to make a new uniform wire. The resistance of new wire
A x molal solution of compound in benzene has a mole fraction of solute equal to 0.2. The value of x is
A wire is stretched between two rigid supports vibrates in its fundamental mode with a frequency of $50 \,Hz$. The mass of the wire is $30 \,g$ and its linear density is $4 \times 10^{-2}\, kg \,m s^{-1}$. The speed of the transverse wave at the string is
A wire is stretched to double its length. The strain is :
A wire of length $36 \,m$ is to be cut into two pieces. One of the pieces is to be made into a square and the other into a circle. What should be the lengths of the two pieces, so that the combined area of the square and the circle is minimum?
A wire of length $L$ has a linear mass density $\mu$ area of cross-section $A$ and Young?? modulus Y. It is suspended vertically from a rigid support. The extension produced in the wire due to its own weight is
A wheel with $20$ metallic spokes each of length $0.8 \,m $ long is rotated with a speed of $120$ revolution per minute in a plane normal to the horizontal component of earth magnetic field $H$ at a place. If $H = 0.4 \times 10^{-4}\, T$ at the place, then induced emf between the axle and the rim of the wheel is
A white precipitate is obtained by the hydrolysis of
A Williamson's synthesis of ethers is an example of
A wire has a mass $(0.3 \pm 0.003)\, g$, radius $(0.5 \pm 0.005)\,cm$ and length $(6 \pm 0.06) \,cm$. The maximum percentage error in the measurement of its density is
A well stoppered thermos flask contains some icecubes. This is an example of
A wheel completes $2000$ revolutions to cover the $9.5\,km$ distance, then the diameter of the wheel is
A water tank standing on the floor has two small holes vertically one above the other punched on one side. The holes are $h_1$ cm and $h_2$ cm above the floor. How high does water stand in the tank when the jets from the holes hit the floor at the same point ?
A weather balloon filled with hydrogen at 1 atm and 27$^\circ$C has volume equal to 1200 litres. On ascending, it reaches a place where temperature is -23$^\circ$C and pressure is 0.5 atm. The volume of the balloon is
A weight $w$ is suspended from, the mid-point of a rope, whose ends are at the same level. In order to make the rope perfectly horizontal, the force applied to each of its ends must be
Which of the following contribute towards photochemical smog formation?
Saline soil contains
Most hazardous metal pollutant of automobile exhausts is
Taj may be destroyed by