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**JEE Advanced**

**Single choice correct**

When Uranium is bombarded with neutrons, it undergoes fission. The fission reaction can be written as

$_{92}U_{235}+_{0}n_{1}⟶_{56}Ba_{141}+_{36}Kr_{92}+3x+Q(energy)$

Where three particles named $x$ are produced and energy $Q$ is released. What is the name of the particle $x$?

$_{92}U_{235}+_{0}n_{1}⟶_{56}Ba_{141}+_{36}Kr_{92}+3x+Q(energy)$

Where three particles named $x$ are produced and energy $Q$ is released. What is the name of the particle $x$?

Two isotopes P and Q of atomic weight 10 and 20, respectively are mixed in equal amount by weight. After 20 days their weight ratio is found to be 1 : 4. Isotope P has a half-life of 10 days. The half-life of isotope Q is

In an experiment the initial number of radioactive nuclei is $3000$. It is found that $1000±40$ nuclei decayed in the $1.0s$. For $∣x∣<<1,ln(1+x)=x$ up to first power in $x$. The error $Δλ$, in the determination of the decay constant $λ$, is $s_{−1}$, is