Q.1
For photoelectric effect to take place, the metal used as the cathode should have ________
Q.2
The unit of magnetic permeability is
Q.3
Which phenomena shows the particle nature of light?
Q.4
According to the quantum theory of light, the energy of light is carried in discrete units are called
Q.5
The energy of a photon, whose momentum is 10 MeV/c, where c is the speed of light, is given by
Q.6
A potentiometer wire is 100 cm long and a constant potential difference is maintained across it. Two cells are connected in series first to support one another and then in opposite direction. The balance points are obtained at 50 cm and 10 cm from the positive end of the wire in the two cases. The ratio of the emf's is :
Q.7
Photon is the fundamental unit/quantum of
Q.8
The energy of a photon varies directly with its
Q.9
A photon of X-ray has energy of 1 keV. A photon of visible radiation has energy of 3 eV. In this context, which one of the following statements is not correct?
Q.10
Suppose voltage V is applied across a resistance R. The power dissipated in the resistance is P. Now the same voltage V is applied across a parallel combination of three equal resistors each of resistance R. Then the power dissipated in the second case will be
Q.11
A galvanometer can be converted into a voltmeter by connecting with it a
Q.12
Resistance of human body in dry condition
Q.13
The threshold frequency is the frequency below which :
Q.14
Which of the following experiments analyzed the Fraunhofer lines of the solar spectrum?
Q.15
Kirchoff's Voltage Law is known as
Q.16
In superconductors, the energy gap is due to
Q.17
Electrical Pressure is also called
Q.18
The purpose of choke in a fluorescent lamp is :
Q.19
Which of the following supports particle nature of photons ?
Q.20
Erg cross Sec is the unit of
Q.21
Super conductors are substances that
Q.22
A galvanometer can be converted to a voltmeter by connecting
Q.23
Which of the following was the first theory of superconductivity?
Q.24
An electron and a proton starting from rest get accelerated through potential difference of 100 kV. The final speed of the electron and the proton are Ve and Vp respectively. Which of the following relations is correct?
Q.25
Which of the following is a device designed to protect electrical devices from voltage spikes?
Q.26
Kirchhoff's laws are applicable to
Q.27
Certain substances loose their electrical resistance completely at super low temperature. Such substances are called.
Q.28
Quality of transmission depends upon
Q.29
Superconductors are those elements
Q.30
The working of the quartz crystal in the watch is based on the
Q.31
The device which converts AC to DC is
Q.32
The potential difference between the terminals of an electric heater is 60 V when it draws a current of 4 A from the source. What current will the heater draw if the potential difference is increased to 127.5 V ?
Q.33
Choose the most appropriate answer: Natural radioactivity was discovered by
Q.34
At the center of the sun, fusion converts hydrogen into
Q.35
A wire carrying current is
Q.36
Circuit breaker usually operate under
Q.37
A device used for converting a.c. into d.c. is called
Q.38
At low temperature, Lead behaves as a :
Q.39
In a nuclear reactor, one of the following is used as a fuel.
Q.40
Alpha particle is the nucleus of an atom of
Q.41
Gamma rays have greatest similarity with
Q.42
In a magnetic field, the direction of motion of a current carrying conductor is given by
Q.43
Carbon Arc lamps are commonly used in
Q.44
Magnetism in materials is due to
Q.45
The domain theory of magnetism applies to
Q.46
The resistance of the human body (dry condition) is of the order of
Q.47
Which component of an IED creates an electrical charge?
Q.48
The device which transfer the signal from low resistance region to high resistance region is
Q.49
The frequency of direct current is ________
Q.50
Energy stored in the nucleus of an atom is called
0 h : 0 m : 1 s