Why a convex lens is called a convergent lens? [For External Candidates]
A convex lens is called a convergent lens because it converges (brings together) parallel rays of light that pass through it.
Question ID: 164
Uploaded on: September 15, 2024
Write with a balanced chemical equation what happens when ethylene reacts with bromine. [For External Candidates]
When ethylene (C₂H₄) reacts with bromine (Br₂), an addition reaction occurs. The double bond in ethylene breaks and bromine atoms add across the carbon atoms, forming 1,2-dibromoethane.
Balanced Chemical Equation:
C2H4 + Br2 → C2H4Br2
Question ID: 165
Uploaded on: September 15, 2024
How is the concept of resistance obtained from Ohm's law? [For External Candidates]
Resistance is derived from Ohm's Law:
R = V/I
This means resistance (R) is the ratio of voltage (V) to current (I). It shows how much a material opposes the flow of electric current.
Question ID: 166
Uploaded on: September 15, 2024
Which among the following gases absorb long wavelength infrared radiation emitted from the earth’s surface?
c. CH4 (Methane)
Explanation: Greenhouse gases like methane (CH₄) absorb long-wavelength infrared radiation emitted by the Earth's surface, trapping heat in the atmosphere.
Question ID: 167
Uploaded on: September 18, 2024
At STP, 2.24 ltr is occupied by
a. 4.4 g CO2
Explanation:
4.4 g CO2:
Molar mass of CO2 = 44 g/mol
Moles of CO2 = 4.4 / 44 = 0.1 mol
Volume = 0.1 × 22.4 = 2.24 L
Question ID: 168
Uploaded on: September 18, 2024
How many molecules of CO2 will be produced when one mole C reacts completely with one mole O2?
a. 6.022 × 10²³
Question ID: 169
Uploaded on: September 18, 2024
For a solid, how many types of thermal expansion coefficients are there?
c. 3
Explanation: For a solid, there are three types of thermal expansion coefficients:
Question ID: 170
Uploaded on: September 18, 2024
Which one of the following has the highest wavelength?
c. Infrared ray
Question ID: 171
Uploaded on: September 18, 2024
In case of refraction, if the angle of incidence and the angle of refraction are 45° and 30° respectively, then the angle of deviation is
b. 15°
Explanation:
The angle of deviation (δ) in refraction is given by the formula:
δ = Angle of incidence − Angle of refraction
Here, the angle of incidence is 45° and the angle of refraction is 30°. So,
δ = 45 ° − 30 ° = 15°
Question ID: 172
Uploaded on: September 18, 2024
Temperature remains unchanged if the potential difference between the two ends of a conductor is V and the current through the conductor is I, which of the following is true?
a. V ∝ I
Explanation: Ohm's Law states that the current (I) flowing through a conductor between two points is directly proportional to the potential difference (V)
V = IR
Question ID: 173
Uploaded on: September 18, 2024
The relation among electromotive force (V), work (W) and charge (Q) is
d. Q = W/V
Question ID: 174
Uploaded on: September 18, 2024
For the atom produced by β-particle emission from a radioactive atom
b. Atomic number increases
Explanation: During β-particle emission (β-decay), a neutron in the nucleus of a radioactive atom is converted into a proton, emitting a β-particle (an electron) and an antineutrino. This process increases the atomic number of the atom by 1.
Question ID: 175
Uploaded on: September 18, 2024