General Science Physics Questions Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, NDA, CDS and All One Day Examinations of India.
1. The joint process of vapourisation and condensation is called:
[A] Sublimation
[B] Chromatography
[C] Distillation
[D] Crystallisation
[C] Distillation
Notes:
Condensation is the change from a vapor to a condensed state (solid or liquid); while, vaporization occurs when a chemical or element is converted from a liquid or a solid to a gas. Distillation is the technique of heating a liquid to create vapor which is collected when cooled separate from the original liquid. It is the joint process of both vaporization and condensation.
2. A concave lens always forms an image which is _________.
[A] Real and erect
[B] Virtual and erect
[C] Real and inverted
[D] Virtual and inverted
[B] Virtual and erect
Notes:
Concave lens possesses at least one surface that curves inwards. It is a diverging lens as it diverges the light rays that are incident parallel to it concave surface. A concave lens is thinner at its centre than at its edges, and is used to correct short-sightedness (myopia). After light rays have passed through the lens, they appear to come from a point called the principal focus. The image formed by a concave lens is virtual, upright, and smaller than the object, and being virtual cannot be projected onto a screen.
3. A light ray travelling from denser to rarer medium at an angle of incidence more than critical angle of concerned media pair suffers.
[A] Reflection
[B] Refraction
[C] Diffraction
[D] Total internal reflection
[D] Total internal reflection
Notes:
If the angle of incidence of light ray in the denser medium is greater than the critical angle of the concerned media pair, the light is not at all reflected into the rarer medium but is totally reflected. This is known as ‘total internal reflection’. The two conditions for total internal reflection to take place include that ray of light must pass from denser into rare medium and second that angle of incidence must be greater than critical angle.
4. Golden view of sea shell is due to which of the following?
[A] Diffraction
[B] Dispersion
[C] Polarization
[D] Reflection
[C] Polarization
Notes:
When a ray of light falls on seashell, its small amount gets refracted (slightly polarized) and rest almost gets reflected back (fully polarized). So it gets a golden view because of polarization.
5. When a bar magnet is cut into two equal halves, the pole strength of each piece will?
[A] Become double
[B] Become half
[C] Become zero
[D] Remain the same
[D] Remain the same
Notes:
The poles remains same whether the magnet is cut into two equal half or more and also pole strength remains same. It is only magnetic moment that reduces due to decrease in the length of the magnet.
6. Flemings “Left hand Rule” is associated with the effect of__:
[A] Electric field on current
[B] Magnetic field on magnet
[C] Electric field on magnet
[D] Magnetic field on current
[D] Magnetic field on current
Notes:
Whenever, a current carrying conductor comes under a magnetic field, there will be force acting on the conductor and on the other hand, if a conductor is forcefully brought under a magnetic field, there will be an induced current in that conductor. In both of the phenomenon, there is a relation between magnetic field, current and force. This relation is directionally determined by Fleming Left Hand rule and Fleming Right Hand rule respectively.
7. Rectifiers are used to convert__:
[A] High voltage to low voltage
[B] Low voltage to high voltage
[C] DC to AC
[D] AC to DC
[D] AC to DC
Notes:
A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as rectification, since it “straightens” the direction of current. Physically, rectifiers take a number of forms, including vacuum tube diodes, mercury-arc valves, etc.
8. When two resistors are connected in parallel, they have__:
[A] Same current
[B] Same potential difference
[C] Different potential difference
[D] Both same current and di fferent potential difference
[B] Same potential difference
Notes:
A potential difference, also called. .voltage, across an electrical component is needed to make a current flow through it. When two resistors are connected in parallel, they have same potential difference.
9. In MRI machine, which one of the following is used?
[A] Sound wave
[B] ‘X’-ray
[C] Ultra-sound wave
[D] Magnetic wave
[D] Magnetic wave
Notes:
Magnetic resonance imaging (MRI), nuclear magnetic resonance imaging (NMRI), or magnetic resonance tomography (MRT) is a medical imaging technique used in radiology to visualize internal structures of the body in detail. MRI makes use of the property of nuclear magnetic resonance (NMR) to image nuclei of atoms inside the body. An MRI scanner is a device in which the patient lies within a large, powerful magnet where the magnetic field is used to align the magnetization of some atomic nuclei in the body, and radio frequency fields to systematically alter the alignment of this magnetization. This causes the nuclei to produce a rotating magnetic field detectable by the scanner. and this information is recorded to construct an image of the scanned area of the body.
10. Which of the following is a semiconductor__?
[A] Silver
[B] Copper
[C] Glass
[D] Silicon
[D] Silicon
Notes:
Silicon is the most used semiconductor for discrete devices and integrated circuits. Its combination of low raw material cost, relatively simple processing, and a useful temperature range makes it currently the best compromise among the various competing materials. Germanium (Ge) was a widely used early semiconductor material but its thermal sensitivity makes it less useful than silicon.