A hydrogen bomb is based on
nuclear fusion
nuclear fission
Both (a) and (b) above
Neither (a) nor (b)
Correct Answer :
A. nuclear fusion
Related Questions
A spherical mirror is
a reflecting elliptical portion
a reflecting spherical surface
a parabolic reflecting surface
a flat reflecting surface
We see the sun before it actually rises on the horizon. This is due to
refraction
reflection
total internal reflection
parallax
Raindrops assume a spherical shape because or
adhesion
surface tension
gravitational force
atmospheric pressure from all sides
The temperature, surface features, length of days and nights of a planet depend on
its atmosphere
its distance from the sun
its rotation
All the above
When a light ray is reflected repeatedly by a set of parallel plane mirrors, the intensity of light ray diminishes alter a few reflections. This is because of
poor reflection from the mirrors
scattering of light from the mirrors
absorption of some light by the mirrors
absorption of light by the atmosphere
Credit for starting Space Science Research in India goes to
HJ Bhabha
SS Bhatnagar
V Sarabhai
CV Raman
Match the following:
| A. Anemometer | 1. Measurement of power |
| B. Tachometer | 2. Wind speed |
| C. Dynamometer | 3. Revolutions per minute |
| D. Barometer | 4. Atmospheric pressure |
| * | 5. Current from a dynamo |
A-1 B-3 C-5 D-4
A-2 B-1 C-3 D-4
A-2 B-3 C-1 D-4
A-1 B-3 C-5 D-2
For an electron orbiting in a hydrogen atom, the necessary centripetal force keeping it in orbit is provided by
the electrical attraction between the negatively charged electron and the positively charged porton
the high speed of the electron
the low speed of the electron
gravity
A rod of brass is held in hand and rubbed with fur. The rod is found to have
no charge
positive charge
negative charge
can't be said
Skating on ice is possible because
the surface of ice is smooth
ice is cold
the pressure on the ice due to skate melts the ice by lowering its melting point forming a thin film of water
the pressure on the ice due to skate raises its melting point
Stars twinkle because of
refraction of light from them through air
reflection
absorption
All the above
A heavenly body similar in nature to the sun intensely hot glowing mass that produces its energy by thermonuclear reactions is
a planet
a meteor
a star
a comet
The cell that can be recharged, after it has run down, by passing a direct current through it from a source of current is
Voltaic cell
Leclanche cell
Dry cell
An accumulator
A stationary elevated object has
kinetic energy
potential energy
momentum
both potential and kinetic energy
Choose the correct answer
Microphone converts sound energy into electrical energy.
Electric fan converts electrical energy into mechanical energy.
Battery converts chemical energy into electrical energy.
All the above
To produce beats it is necessary to have two waves
travelling in opposite direction
of slightly different frequencies
of equal wavelength
of equal amplitude
The maximum displacement of the particle in a mechanical wave motion is known as
amplitude
vibration
frequency
phase
The device used to record the sound is
a microphone
a headphone
a phonograph
an amplifier
A proton is
a quantum of light energy
a quantum of matter
a positively charged atomic particle
another name for positron
The colour of the light which travels through glass with minimum speed is
red
violet
green
yellow
A thermostat is a device used
for automatically maintaining a steady temperature
for measuring electricity
to reduce the voltage of electricity
for producing heat
A bullet is fired at a certain angle with the horizontal. Its path will be
elliptical
a straight line
a parabola
a vertical line
You want a supply of a small but constant current. Which of the following cells will you prefer?
Daniell cell
Leclanche cell
Dry cell
All the above
Lightning conductors are made of
iron
chromium
copper
steel
Formation of shadows can be explained by
rectilinear propagation of light
reflection
refraction
total internal reflection
A solid ball of metal has a spherical cavity inside it. When the ball is heated the volume of the cavity will
increase
decrease
remain unaffected
have its shape changed
When we tighten the string of a sitar or tanpura its pitch
remains the same
increases
decreases
None of the above
The completely dark portion of a shadow of an object is known as
umbra
penumbra
image
black portion of light
If you want a sound proof room, the walls should be
able to refract the sound
good absorbers of sound
good reflectors of sound
All the above
Cosmic rays contain
protons and electrons
alpha particles
gamma rays
All the above