Flash light equipped with a new set of batteries, produces bright white light. As the batteries wear out
the light intensity gets reduced with no change in its colour
light colour changes first to yellow and then red with no change in intensity
it stops working suddenly while giving white light
colour changes to red and also intensity gets reduced
If a street light of mass Mis suspended from the end of a uniform rod of length L in different possible patterns as shown in figure, then
pattern A is more sturdy
pattern B is more study
pattern C is more sturdy
all will have same sturdiness
has 92 protons and 238 nucleons. It decays by emitting an alpha particle and becomes
B.
Emission of alpha particle, decrease the mass number by 4 and charge number by 2.
∴ Decrease in mass number = 238 - 3 = 234
Decrease in charge number = 92 - 2= 90
is emitted.
The foil bone has a 14C : 12C ratio, which is [ 1/16 ] of that in a living animal bone. If the half-life time of 14C is 5730 years, then the age of the fossil bone is
11460 years
17190 years
22920 years
45840 years
If alpha, beta and gamma rays carry same momentum, which has the longest wavelength?
Alpha rays
Beta rays
Gamma rays
None, all have same wavelength
A light emitting diode (LED) has a voltage drop of 2 volt across it and passes a current of 10 mA when it operates with a 6 volt battery through a limiting resistor R. The value of R is
40 kΩ
4 kΩ
200 kΩ
400 kΩ
The minimum potential difference between the base and emitter required to switched a silicon transistor ON is approximately
1 V
3 V
5 V
4.2 V