List of top Physics Questions

In an a.c. circuit, the rms voltage is \(100\sqrt{2}\) V. The peak value of voltage would be:
Two protons P and Q are placed between two charged plates A and B as shown, then
2 protons
At what distance should an object be placed from a convex lens of focal length 15 cm to obtain a real image three times the size of the object?
What is the self inductance of a solenoid of length 50 cm, if area of cross section is 10 cm2 and total number of turns is 600?
Consider two different hydrogen atoms. The electron in each atom is in first excited state. According to Bohr's model, electrons will have:
Choose the correct formula for magnifying power of a simple microscope from the following
Two wires of copper have lengths L and 2L and cross sectional area 2A and A, respectively. The ratio of their specific resistance would be-
Electron and Photon have same de Broglie wavelength, which of the following is true for their momentum:
The potential of a uniformly charged spherical shell at a point r/2 from its centre is 5 V. The potential at its surface is:
(Given radius of shell = r)
Which of the following statements are correct?
A. Number of photoelectrons emitted per second is directly proportional to the intensity of incident radiation
B. Cut off potential is the minimum negative potential given to the plate for which photocurrent becomes maximum
C. For a given frequency of the incident radiation, the stopping potential is independent of its intensity
D. Even for the exceedingly dim incident radiation apparent time lag is~ 109s or less
E. Photons are electrically neutral and are not deflected by electric and magnetic fields
Choose the correct answer from the options given below:
Two point charges \(q\) and \(-3q\) are kept 12 cm apart. The distance of the point from \(q\) on the line between two charges at which potential due to this system of charges is zero will be:
C.V. Raman got Nobel Prize in 1930 for his discovery of:
A conducting sphere of radius R is given a charge Q. What is the electric field and the electric potential at the centre of the sphere?
What is the wavelength of light for the least energetic photon emitted in the Lyman series of the hydrogen atom spectrum lines?
(Take h=6.63×10-34Js; c=3×108 ms-1; e=1.6×10-19C)
Four identical capacitors each of capacitance C are arranged as shown in the figure. What is the effective capacitance between P and Q?
Capacitance
A spherical conducting shell of inner radius r₁ and outer radius r₂ has a charge Q. A charge q is placed at the centre of the shell. The surface charge density on outer surface of the shell is:
Energy band gap is maximum in:
Which of the following is a transducer ?
(A) Loudspeaker
(B) Amplifier
(C) Rectifier
(D) Microphone
Choose the correct answer from the options given below :
A semiconductor has an electron concentration of 8 x 1013 m-3 and hole concentration of 2 × 103 m-3. The semiconductor behaves as:
SI unit of temperature is ________.
Kirchhoff's Second Law is based on law of conservation of:
A \(ẞ\)-particle is moving perpendicular to the uniform electric field created by a potential difference of \(6 × 10^3\) V across parallel metal plates separated by a vertical distance of 6 cm. What is the acceleration of the beta particle between the plates? (Mass of electron = \(9.1 × 10^{-31}\)kg) 
A vertical electric field of magnitude 4.9×105 NC-1 just prevents a water droplet of mass 0.1 g from falling. What is the charge on the droplet? Take acceleration due to gravity 9.8 ms-2.
The type of wavefront that emerges from a distant light source is:
When 100 V dc is applied across a solenoid, a current of 1 A flows in it. When 100 V ac is applied across the same solenoid the current drops to 0.5 A. If the frequency of the ac source is 50 Hz, the impedance and inductance of the solenoid are: