List of top Questions asked in COMEDK UGET

When two objects are moving along a straight line in the same direction, the distance between them increases by 6 m in one second. If the objects move with their constant speed towards each other, the distance decreases by 8 m in one second. Then the speed of the objects are:

Two point charges M and N having charges +q and -q respectively are placed at a distance apart. Force acting between them is F. If 30% of charge of N is transferred to M, then the force between the charges becomes:

A stone of mass 2 kg is hung from the ceiling of the room using two strings. If the strings make an angle $ 60^\circ $ and $ 30^\circ $ respectively with the horizontal surface of the roof, then the tension on the longer string is:
The Enthalpy of combustion of C$_6$H$_6$COOH(s) at 25$^\circ$C and 1.0 atm pressure is -2546 kJ/mol. What is the Internal energy change for this reaction?

If the ratio of lengths, radii and Young's Moduli of steel and brass wires in the figure are $ a $, $ b $, and $ c $ respectively, then the corresponding ratio of increase in their lengths would be:

A parallel plate capacitor is filled by a dielectric whose relative permittivity varies with the applied voltage (U) as $ \epsilon = 2U $. A similar capacitor with no dielectric is charged to $ U_0 = 78 \, \text{V} $. It is then connected to the uncharged capacitor with the dielectric. Find the final voltage on the capacitors.
Two metal spheres, one of radius $ \frac{R}{2} $ and the other of radius $ 2R $ respectively have the same surface charge density. They are brought in contact and separated. The ratio of their new surface charge densities is:

Two charges $ -q $ each are fixed, separated by distance $ 2d $. A third charge $ q $ of mass $ m $ placed at the mid-point is displaced slightly by $ x' (x \ll d) $ perpendicular to the line joining the two fixed charges as shown in the figure. The time period of oscillation of $ q $ will be:

An electric bulb of volume 300 cm$^3$ was sealed off during manufacture at a pressure of 1 mm of mercury at 27°C. The number of air molecules contained in the bulb is, (R = 8.31 J mol$^{-1}$ K$^{-1}$ and $N_A = 6.02 \times 10^{23}$)
The width of the fringes obtained in the Young's double slit experiment is 2.6 mm when light of wavelength 6000$^\circ$A is used. If the whole apparatus is immersed in a liquid of refractive index 1.3 the new fringe width will be:
Two circular coils of radius 'a' and '2a' are placed coaxially at a distance 'x' and '2x' respectively from the origin along the X-axis. If their planes are parallel to each other and perpendicular to the X-axis and both carry the same current in the same direction, then the ratio of the magnetic field induction at the origin due to the smaller coil to that of the bigger one is:

Five charges, 'q' each are placed at the corners of a regular pentagon of side 'a' as shown in figure. First, charge from 'A' is removed with other charges intact, then charge at 'A' is replaced with an equal opposite charge. The ratio of magnitudes of electric fields at O, without charge at A and that with equal and opposite charge at A is

Though Sn and Si are 4th group elements, Sn is a metal while Si is a semiconductor because
A one kg block of ice at $ -1.5^\circ C $ falls from a height of 1.5 km and is found melting. The amount of ice melted due to fall, if 60% energy is converted into heat is (Specific heat capacity of ice is 0.5 cal g$^{-1}$ C$^{-1}$, Latent heat of fusion of ice = 80 cal g$^{-1}$)
The closest approach of an alpha particle when it makes a head-on collision with a gold nucleus is $ 10 \times 10^{-14} $ m. Then the kinetic energy of the alpha particle is:

If potential (in volt) in a region is expressed as $ V(x, y, z) = 6xy - y + 2yz $, the electric field (in} $ \text{N/C} $ at point (1, 0, 1) is:

Which of the given dimensional formula represents heat capacity?
A circular coil of radius 0.1 m is placed in the X-Y plane and a current 2 A is passed through the coil in the clockwise direction when looking from above. Find the magnetic dipole moment of the current loop.
A cubical box of side 1 m contains Boron gas at a pressure of 100 Nm$^{-2}$. During an observation time of 1 second, an atom travelling with the rms speed parallel to one of the edges of the cube, was found to make 500 hits with a particular wall, without any collision with other atoms. The total mass of gas in the box in gram is:
A string of length 25 cm and mass $ 10^{-3} $ kg is clamped at its ends. The tension in the string is 2.5 N. The identical wave pulses are generated at one end and at regular interval of time, $ \Delta t $. The minimum value of $ \Delta t $, so that a constructive interference takes place between successive pulses is:

The difference in energy levels of an electron at two excited levels is 13.75 eV. If it makes a transition from the higher energy level to the lower energy level then what will be the wavelength of the emitted radiation? 
Given:
$ h = 6.6 \times 10^{-34} \, \text{m}^2 \, \text{kg} \, \text{s}^{-1} $, $ c = 3 \times 10^8 \, \text{ms}^{-1} $, $ 1 \, \text{eV} = 1.6 \times 10^{-19} \, \text{J} $

On increasing the temperature of a conductor, its resistance increases because
When light wave passes from a medium of refractive index $ \mu $ to another medium of refractive index $ 2\mu $, the phase change occurs to the light is:
Which of the following statement is true regarding the centre of mass of a system?
An ideal diode is connected in series with a capacitor. The free ends of the capacitor and the diode are connected across a 220 V ac source. Now the potential difference across the capacitor is: