1. Frequency is the number of complete waves that pass a point in a second. 2.Wavelength is the distance between two crests or two troughs. 3.Time period <span> is the time it takes for one complete wave to pass a given point. 4. Amplitude is the height of the wave. Hence option 4 is correct. </span>
Answer
t = 367.77 s = 6.13 min
Explanation:
According to the law of conservation of energy:
where,
P = Electric Power of Heater = 300 W
t = time required = ?
m_g = mass of glass = 300 g = 0.3 kg
m_w = mass of water = 250 g = 0.25 kg
C_g = speicific heat of glass = 840 J/kg.°C
C_w = specific heatof water = 4184 J/kg.°C
ΔT_g = ΔT_w = Change in Temperature of Glass and water = 100°C - 15°C
ΔT_g = ΔT_w = 85°C
Therefore,
<u>t = 367.77 s = 6.13 min</u>
The correct answer is
C. The battery
The battery is a device that provides a potential difference in the circuit, and so an electromotive force (e.m.f.) which pushes the electrons in the circuit from the negative pole towards the positive pole of the battery, so they move through the circuit. Therefore, it provides electrical energy.
Electron configurations:
Ge: [Ar] 3d10 4s2 4p2 => 6 electrons in the outer shell
Br: [Ar] 3d10 4s2 4p5 => 7 electrons in the outer shell
Kr: [Ar] 3d10 4s2 4p6 => 8 electrons in the outer shell
The electron affinity or propension to attract electrons is given by the electronic configuration. Remember that the most stable configuration is that were the last shell is full, i.e. it has 8 electrons.
The closer an atom is to reach the 8 electrons in the outer shell the bigger the electron affinity.
Of the three elements, Br needs only 1 electron to have 8 electrons in the outer shell, so it has the biggest electron affinity (the least negative).
Ge: needs 2 electrons to have 8 electrons in the outer shell, so it has a smaller (more negative) electron affinity than Br.
Kr, which is a noble gas, has 8 electrons and is not willing to attract more electrons at all, the it has the lowest (more negative) electron affinity of all three to the extension that really the ion is so unstable that it does not make sense to talk about a number for the electron affinity of this atom.
