11) Which one of the following colours has the longest wavelength?
(A) Green
(B) Yellow
(C) Blue
(D) Red
12) Which one of the following can be used to focus sunlight?
(A) Plane mirror
(B) Concave lens
(C) Concave mirror
(D) Convex mirror
13) Which of the following is a good conductor of electricity
(A) PVC
(B) Glass
(C) Rubber
(D) Graphite
14) The tendency of a liquid drop to contract and occupy minimum area is due to
(A) Surface tension
(B) Viscosity
(C) Density
(D) Vapour pressure
15) Choke coil is a coil of
(A) High resistance and high inductance
(B) Low resistance and high inductance
(C) High resistance and low inductance
(D) Low resistance and low inductance
16) Conductors, insulators and semi-conductors differ from each other due to property of
(A) Ability of the current they carry
(B) Formation of crystal lattice
(C) Binding energy of their electrons
(D) Mutual width of their energy gaps
17) On which principle does the tape recorder function?
(A) Electromagnetic Induction
(B) Electrovalency
(C) Gay Lussac's law of combining volumes
(D) Boyle's Law
18) When a constant force is applied to a body it moves with uniform
(A) Momentum
(B) Velocity
(C) Speed
(D) Acceleration
19) The silvered surface of thermosflask prevents transfer of heat by
(A) Conduction
(B) Convection
(C) Reflection
(D) Radiation
20) When wind blows at high velocity, roof tops are blown off because pressure
(A) Outside is more than inside the roof
(B) Inside is more than outside the roof
(C) Increase due to wind velocity
(D) Is exerted by air from outside