Q.1
A small sphere of radius \(r\) falls from rest in a viscous liquid. As a result, heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity, is proportional to
  • \(r^3\)
  • \(r^4\)
  • \(r^2\)
  • \(r^5\)
Q.2
The power radiated by a black body is P and it radiates maximum energy at wavelength, \(\lambda _0\). If the temperature of the black body is now changed so that it radiates maximum energy at wavelength \(\frac{3}{4}\lambda _{0}\), the power radiated by it becomes \(nP\). The value of \(n\) is
  • \( \frac{4}{3}\)
  • \( \frac{256}{81}\)
  • \( \frac{3}{4}\)
  • \( \frac{81}{256}\)
Q.3
An inductor \(20 \,m H\), a capacitor \(100\mu  F\) and a resistor \(50\Omega \) are connected in series across a source of emf, \(V=\text{10}\sin\text{314 }t\). The power loss in the circuit is
  • 0.79 W
  • 0.43 W
  • 1.13 W
  • 2.74 W
Q.4
The kinetic energies of a plant in an elliptical orbit about the sun, at positions A,B and C are \(k_A,k_B\,\,and\,\,k_C\), respectively. AC is the major axis and SB is perpendicular to AC at the position of the sun S as shown in the figure. Then
neet-18-ph-q39.png
  • \(K_A < K_B < K_C\)
  • \(K_B < K_A < K_C\)
  • \(K_A > K_B > K_C\)
  • \(K_B > K_A > K_C\)
Q.5
A sample of 0.1 g water at \(100^0\text{C}\) and normal pressure \(\left( 1.013\times 10^5\text{Nm}^{-2} \right) \) requires 54 cal of heat energy to convert to steam at \(100^0\text{C}\). If the volume of the steam produced  is 167.1 cc, the change in internal energy of the sample, is
  • 84.5 J
  • 208.7 J
  • 104.3 J
  • 42.2 J
Q.6
A block of mass \(m\) is placed on a smooth inclined wedge ABC of inclination \(\theta\) as shown in the figure. The wedge is given acceleration \(a\) towards the right. The relation between a and  \(\theta\)  for the block to remain stationary on the wedge is
neet-18-ph-q35.png
  • \(a=\frac{g}{\mathrm{cosec}\theta}\)
  • \(a=g\tan\theta\)
  • \(a=\frac{g}{\sin\theta}\)
  • \(a=g\cos\theta\)
Q.7
A carbon resistor of (47 + 4.7) is to be marked with rings of different colors for its identification. The color code sequence will be
  • Yellow – Violet – Orange – Silver
  • Yellow – Green – Violet – Gold
  • Green – Orange – Violet – Gold
  • Violet – Yellow – Orange – Silver
Q.8
A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from
  • the current source
  • the magnetic field
  • the induced electric field due to the changing magnetic field
  • the lattice structure of the material of the rod
Q.9
A metallic rod of mass per unit length \(\text{0.5Kgm}^{-1}\) is lying horizontally on a smooth inclined plane which makes an angle of  with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction \(0.25\,\, T\) is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is
  • 7.14 A
  • 5.98 A
  • 14.76 A
  • 11.32 A
Q.10
Current sensitivity of a moving coil galvanometer is 5 div/mA and its voltage sensitivity (angular deflection per unit voltage applied) is 20 div/V. The resistance of the galvanometer is
  • \(40\Omega \)
  • \(250\Omega \)
  • \(25\Omega \)
  • \(500 \Omega \)
Q.11
A solid sphere is in rolling motion. In rolling motion a body possesses translational kinetic energy \(\left( K_t \right) \) as well as rotational kinetic energy \(\left( K_r \right)\) simultaneously. The ratio \(K_t:\left( K_t+K_r \right)\) for the sphere is
  • 5: 7
  • 7: 10
  • 10: 7
  • 2: 5
Q.12
When the light of frequency \(2v_0\) (where \(v_0\) is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is \(v_1\) . When the frequency of the incident radiation is increased to \(5v_0\), the maximum velocity of electrons emitted from the same plate is \(v_2\)  The ratio of \(v_1\)  to \(v_2\)  is
  • 4: 1
  • 1: 2
  • 1: 4
  • 2: 1
Q.13
An em wave is propagating in a medium with a velocity \(\vec{V} = V \hat{i}\). The instantaneous oscillating electric field of his em wave is along +y axis. Then the direction of oscillating magnetic field of the em wave will be along
  • – y direction
  • – x direction
  • + z direction
  • – z direction
Q.14
In a p-n junction diode, change in temperature due to heating
  • affects only reverse resistance
  • affects only forward resistance
  • affects the overall V –I characteristics of p-n junction
  • does not affect resistance of p-n junction
Q.15
A solid sphere is roasting freely about its symmetry axis in free space. The radius of the sphere is increased keeping its mass same. Which of the following physical quantities would remain constant for the sphere?
  • Angular velocity
  • Moment of inertia
  • Rotational kinetic energy
  • Angular momentum
Q.16
The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is
  • 6.25%
  • 26.8%
  • 20%
  • 12.5%
Q.17
Which one is wrongly matched?
  • Gemma cups – Marchantia
  • Uniflagellate gametes – Polysiphonia
  • Biflagellate zoospores – Brown algae
  • Unicellular organism – Chlorella
Q.18
The similarity of bone structure in the forelimbs of many vertebrates is an example of
  • Adaptive radiation
  • Homology
  • Analogy
  • Convergent evolution
Q.19
According to Hugo de Vries, the mechanism of evolution is
  • Minor mutations
  • Saltation
  • Phenotypic variations
  • Multiple step mutations
Q.20
Which of the following pairs is wrongly matched?
  • XO type sex determination : Grasshopper
  • ABO blood grouping : Co-dominance
  • T.H. Morgan : Linkage
  • Starch synthesis in pea : Multiple alleles
Q.21
The correct order of steps in Polymerase Chain Reaction (PCR) is
  • Denaturation, Annealing, Extension
  • Denaturation, Extension, Annealing
  • Annealing, Extension, Denaturation
  • Extension, Denaturation, Annealing
Q.22
Many ribosomes may associate with a single mRNA to form multiple copies of a polypeptide simultaneously. Such strings of ribosomes are termed as
  • Polysome
  • Plastidome
  • Polyhedral bodies
  • Nucleosome
Q.23
Use of bioresources by multinational companies and organizations without authorisation from the concerned country and its people is called
  • Biopiracy
  • Bio-infringemen
  • Biodegradation
  • Bioexploitation
Q.24
In stratosphere, which of the following elements acts as a catalyst in degradation of ozone and release of molecular oxygen?
  • Cl
  • Oxygen
  • Carbon
  • Fe
Q.25
Hormones secreted by the placenta to maintain pregnancy are
  • hCG, hPL, progestogens, prolactin
  • hCG, hPL, progestogens, estrogens
  • hCG, progestogens, estrogens, glucocorticoids
  • hCG, hPL, estrogens, relaxin, oxytocin
Q.26
Stomatal movement is not affected by
  • \(CO_2\) concentration
  • Light
  • \(O_2\) concentration
  • Temperature
Q.27
Which of these statements is incorrect?
  • Enzymes of TCA cycle are present in mitochondrial matrix
  • Glycolysis occurs in cytosol
  • Oxidative phosphorylation takes place in outer mitochondrial membrane
  • Glycolysis operates as long as it is supplied with NAD that can pick up hydrogen atoms
Q.28
Which among the following is not a prokaryote?
  • Oscillatoria
  • Saccharomyces
  • Nostoc
  • Mycobacterium
Q.29
Match the columns
Column I Column II
a. Herbarium (i) It is a place having a
collection of preserved
plants and animals
b. Key (ii) A list that enumerates
methodically all the
species found in an area
with brief description
aiding identification
c. Museum (iii) Is a place where dried
and pressed plant
specimens mounted on
sheets are kept
d. Catalogue (iv) A booklet containing a
list of characters and
their alternates which
are helpful in
identification of various
taxa.
  • a. -- (iii) b. -- (iv) c. -- (i) d. -- (ii)
  • a. -- (ii) b. -- (iv) c. -- (iii) d. -- (i)
  • a. -- (iii) b. -- (ii) c. -- (i) d. -- (iv)
  • a. -- (i) b. -- (iv) c. -- (iii) d. -- (ii)
Q.30
Which of the following features is used to identify a male cockroach from a female cockroach?
  • Presence of anal cerci
  • Presence of a boat shaped sternum on the 9th abdominal segment
  • Presence of caudal styles
  • Forewings with darker tegmina
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