Jamb 2018 Flashcards
(22 cards)
The image formed a mirror is
Erect, laterally inverted and same distance from the mirror as the object
Why do white light undergo dispersion in a glass prism?
Different constituents of light move at different speed glass
Explain the cause of mirage
Layers of air have different refractive index near the road surface in hot weathers
Light from the sky can be retracted upward after coming close to the surface of the road
Which of the following has the lowest internal resistance when new?
A. Leclanche cell
B. Daniell cell
C. Torch battery
D. Accumulator
Accumulator
Does nuclear fission lead to a chain reaction?
YES
If the fraction of the atoms of a radioactive material left after 120years is 1/64
, what is the half-life of the substance
20 years
A positively charged rod X is brought near an uncharged metal sphere Y and is then touched by a finger with X still in place. When the finger is removed, the result is that Y has
A. no charge and a zero potential
B. a positive charge and a zero potential
C. a negative charge and a positive potential
D. a negative charge and a negative potential
D
Image of convex mirror is
Erect, virtual and diminished
In homes, electrical appliances and lamps are connected in parallel because
Series connection uses high voltage
The energy needed to move a unit positive charge around a complete electric circuit is called the
A. electromotive force
B. electric potential difference
C. electric energy
D. kinetic energy
B
solid cube of side 50cm and mass 75kg floats in a liquid with 13
of its height above the liquid surface. The relative density of the liquid is?
A. 0.33
B. 0.50
C. 0.67
D. 0.90
D
What is the function of a fuse?
Fuse wires have a low melting point so that if a huge amount of current is passed through it to any appliance than that wire would melt and stop the appliance from getting damaged by not letting the current pass any further.
The process by which protons are converted into helium atoms with a tremendous release of energy is called?
A. thermionic emission
B. nuclear fission
C. thermonuclear fusion
D. photoelectric emission
C
What is not a product of nuclear fusion?
X-ray
Which of the following phenomena cannot be explained by the molecular theory of matter?
A. Conduction
B. Convection
C. Expansion
D. Radiation
D
A particle of mass M initially at rest splits into two. If one of the particles of mass M1 moves with velocity V1 , the second particle moves with velocity
M1V1/M1 - M
The efficiency of energy conversion on the energy flow through a hydroelectric power is?
Efficiency = useful energy output from machine / energy input into machine
= E3 / E2
An object weighs 30N in air and 21N in water. The weight of the object when completely immersed in a liquid of relative density 1.4 is
A. 25.2N
B. 17.4N
C. 12.6N
D. 9.0N
B
The image of an object is located 6cm behind a convex mirror. If it’s magnification is 0.6, calculate the focal length of the mirror
A. 3.75cm
B. 6.70cm
C. 10.00cm
D. -15.00cm
D
If the focal length of a camera is 20cm, the distance from the film at which the lens must be set to produce a sharp image of 100cm away is
A. 17cm
B. 20cm
C. 25cm
D. 100cm
A
When a known standard resistor of 2.0 is connected to the 0.0cm end of a metre bridge, the balance point is found to be at 55.0cm
A. 1.10Ω
B. 1.64Ω
C. 2.44Ω
D. 27.50Ω
C
A solid weighs 45N and 15N respectively in air and water. Determine the relative density of the solid
A. 0.33
B. 0.50
C. 1.50
D. 3.00
C
Rd = weight of solid in air/weight of solid in air - weight solid in water
